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数据库大作业代码展示

2020-06-02 09:40:20 作者：互联网

在评论区里说代码垃圾之前，我先说了：这代码写的挺垃圾的。在即将完成一半的时候意识到了，代码冗余太多，基本没有遵循DRY原则，还能再降低一些代码的耦合性。高内聚低耦合，刚听别人讲这个概念时没怎么听懂，只是跟着把代码示例写了一下，现在想想，那个例子的代码确实挺好的。

在CSDN上放全部代码不是很方便，所以挑了一些比较集中的代码在这里做了展示，完整的源码放GitHub上了https://github.com/Cheng-xiaozhen/Educational-Administration-Management

首先是数据库方面的代码

采用生成脚本的方式，生成的代码。

USE [master]
GO
/****** Object:  Database [EAMDatabase]    Script Date: 2020/5/29 16:03:59 ******/
CREATE DATABASE [EAMDatabase]
 CONTAINMENT = NONE
 ON  PRIMARY 
( NAME = N'EAMDatabase', FILENAME = N'D:\C# for vs\Educational Administration Management\EAMDatabase.mdf' , SIZE = 8192KB , MAXSIZE = UNLIMITED, FILEGROWTH = 65536KB )
 LOG ON 
( NAME = N'EAMDatabase_log', FILENAME = N'D:\C# for vs\Educational Administration Management\EAMDatabase_log.ldf' , SIZE = 73728KB , MAXSIZE = 2048GB , FILEGROWTH = 65536KB )
GO
ALTER DATABASE [EAMDatabase] SET COMPATIBILITY_LEVEL = 140
GO
IF (1 = FULLTEXTSERVICEPROPERTY('IsFullTextInstalled'))
begin
EXEC [EAMDatabase].[dbo].[sp_fulltext_database] @action = 'enable'
end
GO
ALTER DATABASE [EAMDatabase] SET ANSI_NULL_DEFAULT OFF 
GO
ALTER DATABASE [EAMDatabase] SET ANSI_NULLS OFF 
GO
ALTER DATABASE [EAMDatabase] SET ANSI_PADDING OFF 
GO
ALTER DATABASE [EAMDatabase] SET ANSI_WARNINGS OFF 
GO
ALTER DATABASE [EAMDatabase] SET ARITHABORT OFF 
GO
ALTER DATABASE [EAMDatabase] SET AUTO_CLOSE OFF 
GO
ALTER DATABASE [EAMDatabase] SET AUTO_SHRINK OFF 
GO
ALTER DATABASE [EAMDatabase] SET AUTO_UPDATE_STATISTICS ON 
GO
ALTER DATABASE [EAMDatabase] SET CURSOR_CLOSE_ON_COMMIT OFF 
GO
ALTER DATABASE [EAMDatabase] SET CURSOR_DEFAULT  GLOBAL 
GO
ALTER DATABASE [EAMDatabase] SET CONCAT_NULL_YIELDS_NULL OFF 
GO
ALTER DATABASE [EAMDatabase] SET NUMERIC_ROUNDABORT OFF 
GO
ALTER DATABASE [EAMDatabase] SET QUOTED_IDENTIFIER OFF 
GO
ALTER DATABASE [EAMDatabase] SET RECURSIVE_TRIGGERS OFF 
GO
ALTER DATABASE [EAMDatabase] SET  DISABLE_BROKER 
GO
ALTER DATABASE [EAMDatabase] SET AUTO_UPDATE_STATISTICS_ASYNC OFF 
GO
ALTER DATABASE [EAMDatabase] SET DATE_CORRELATION_OPTIMIZATION OFF 
GO
ALTER DATABASE [EAMDatabase] SET TRUSTWORTHY OFF 
GO
ALTER DATABASE [EAMDatabase] SET ALLOW_SNAPSHOT_ISOLATION OFF 
GO
ALTER DATABASE [EAMDatabase] SET PARAMETERIZATION SIMPLE 
GO
ALTER DATABASE [EAMDatabase] SET READ_COMMITTED_SNAPSHOT OFF 
GO
ALTER DATABASE [EAMDatabase] SET HONOR_BROKER_PRIORITY OFF 
GO
ALTER DATABASE [EAMDatabase] SET RECOVERY FULL 
GO
ALTER DATABASE [EAMDatabase] SET  MULTI_USER 
GO
ALTER DATABASE [EAMDatabase] SET PAGE_VERIFY CHECKSUM  
GO
ALTER DATABASE [EAMDatabase] SET DB_CHAINING OFF 
GO
ALTER DATABASE [EAMDatabase] SET FILESTREAM( NON_TRANSACTED_ACCESS = OFF ) 
GO
ALTER DATABASE [EAMDatabase] SET TARGET_RECOVERY_TIME = 60 SECONDS 
GO
ALTER DATABASE [EAMDatabase] SET DELAYED_DURABILITY = DISABLED 
GO
EXEC sys.sp_db_vardecimal_storage_format N'EAMDatabase', N'ON'
GO
ALTER DATABASE [EAMDatabase] SET QUERY_STORE = OFF
GO
USE [EAMDatabase]
GO
/****** Object:  Table [dbo].[Class]    Script Date: 2020/5/29 16:04:00 ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
CREATE TABLE [dbo].[Class](
	[CLID] [varchar](11) NOT NULL,
	[CLName] [nvarchar](10) NOT NULL,
 CONSTRAINT [PK_Class] PRIMARY KEY CLUSTERED 
(
	[CLID] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY],
 CONSTRAINT [UQ_Class_CLID] UNIQUE NONCLUSTERED 
(
	[CLID] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
) ON [PRIMARY]
GO
/****** Object:  Table [dbo].[College]    Script Date: 2020/5/29 16:04:00 ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
CREATE TABLE [dbo].[College](
	[COID] [varchar](11) NOT NULL,
	[COName] [nvarchar](12) NOT NULL,
 CONSTRAINT [PK_College] PRIMARY KEY CLUSTERED 
(
	[COID] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY],
 CONSTRAINT [UQ_College_COID] UNIQUE NONCLUSTERED 
(
	[COID] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
) ON [PRIMARY]
GO
/****** Object:  Table [dbo].[Course]    Script Date: 2020/5/29 16:04:00 ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
CREATE TABLE [dbo].[Course](
	[CID] [varchar](11) NOT NULL,
	[CName] [nvarchar](10) NOT NULL,
	[Departments] [varchar](11) NOT NULL,
	[Teacher] [varchar](11) NOT NULL,
 CONSTRAINT [PK_Course] PRIMARY KEY CLUSTERED 
(
	[CID] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY],
 CONSTRAINT [UQ_Course_CID] UNIQUE NONCLUSTERED 
(
	[CID] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
) ON [PRIMARY]
GO
/****** Object:  Table [dbo].[Student]    Script Date: 2020/5/29 16:04:00 ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
CREATE TABLE [dbo].[Student](
	[StudentID] [varchar](11) NOT NULL,
	[PassWord] [varchar](50) NOT NULL,
	[StudentName] [nvarchar](10) NOT NULL,
	[StudentGender] [bit] NOT NULL,
	[Birthday] [datetime] NOT NULL,
	[AdmissionTime] [datetime] NOT NULL,
	[Departments] [varchar](11) NOT NULL,
	[Class] [varchar](11) NOT NULL,
	[Image] [image] NULL,
 CONSTRAINT [PK_Student] PRIMARY KEY CLUSTERED 
(
	[StudentID] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY],
 CONSTRAINT [UQ_Student_SID] UNIQUE NONCLUSTERED 
(
	[StudentID] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
) ON [PRIMARY] TEXTIMAGE_ON [PRIMARY]
GO
/****** Object:  Table [dbo].[Student_Grade]    Script Date: 2020/5/29 16:04:00 ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
CREATE TABLE [dbo].[Student_Grade](
	[AutoID] [int] IDENTITY(1,1) NOT NULL,
	[SID] [varchar](11) NOT NULL,
	[CID] [varchar](11) NOT NULL,
	[Score] [float] NULL,
 CONSTRAINT [PK_Student_Grade_1] PRIMARY KEY CLUSTERED 
(
	[AutoID] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY],
 CONSTRAINT [UQ_Student_Grade_SIDCID] UNIQUE NONCLUSTERED 
(
	[SID] ASC,
	[CID] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
) ON [PRIMARY]
GO
/****** Object:  Table [dbo].[Teacher]    Script Date: 2020/5/29 16:04:00 ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
CREATE TABLE [dbo].[Teacher](
	[TID] [varchar](11) NOT NULL,
	[PassWord] [varchar](50) NOT NULL,
	[TName] [nvarchar](10) NOT NULL,
	[TGender] [bit] NOT NULL,
	[Birthday] [datetime] NOT NULL,
	[AdmissionTime] [datetime] NOT NULL,
	[Departments] [varchar](11) NOT NULL,
	[TSalary] [money] NOT NULL,
	[Image] [image] NULL,
	[Address] [nvarchar](20) NOT NULL,
 CONSTRAINT [PK_Teacher] PRIMARY KEY CLUSTERED 
(
	[TID] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY],
 CONSTRAINT [UQ_Teacher_TID] UNIQUE NONCLUSTERED 
(
	[TID] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
) ON [PRIMARY] TEXTIMAGE_ON [PRIMARY]
GO
ALTER TABLE [dbo].[Student] ADD  CONSTRAINT [DF_Student_StudentGender]  DEFAULT ((1)) FOR [StudentGender]
GO
ALTER TABLE [dbo].[Teacher] ADD  CONSTRAINT [DF_Teacher_TGender]  DEFAULT ((1)) FOR [TGender]
GO
ALTER TABLE [dbo].[Course]  WITH CHECK ADD  CONSTRAINT [FK_Course_College] FOREIGN KEY([Departments])
REFERENCES [dbo].[College] ([COID])
ON DELETE CASCADE
GO
ALTER TABLE [dbo].[Course] CHECK CONSTRAINT [FK_Course_College]
GO
ALTER TABLE [dbo].[Course]  WITH CHECK ADD  CONSTRAINT [FK_Course_Teacher] FOREIGN KEY([Teacher])
REFERENCES [dbo].[Teacher] ([TID])
ON DELETE CASCADE
GO
ALTER TABLE [dbo].[Course] CHECK CONSTRAINT [FK_Course_Teacher]
GO
ALTER TABLE [dbo].[Student]  WITH CHECK ADD  CONSTRAINT [FK_Student_Class] FOREIGN KEY([Class])
REFERENCES [dbo].[Class] ([CLID])
ON DELETE CASCADE
GO
ALTER TABLE [dbo].[Student] CHECK CONSTRAINT [FK_Student_Class]
GO
ALTER TABLE [dbo].[Student]  WITH CHECK ADD  CONSTRAINT [FK_Student_College] FOREIGN KEY([Departments])
REFERENCES [dbo].[College] ([COID])
GO
ALTER TABLE [dbo].[Student] CHECK CONSTRAINT [FK_Student_College]
GO
ALTER TABLE [dbo].[Student_Grade]  WITH CHECK ADD  CONSTRAINT [FK_Student_Grade_Course] FOREIGN KEY([CID])
REFERENCES [dbo].[Course] ([CID])
ON DELETE CASCADE
GO
ALTER TABLE [dbo].[Student_Grade] CHECK CONSTRAINT [FK_Student_Grade_Course]
GO
ALTER TABLE [dbo].[Student_Grade]  WITH CHECK ADD  CONSTRAINT [FK_Student_Grade_Student] FOREIGN KEY([SID])
REFERENCES [dbo].[Student] ([StudentID])
ON DELETE CASCADE
GO
ALTER TABLE [dbo].[Student_Grade] CHECK CONSTRAINT [FK_Student_Grade_Student]
GO
ALTER TABLE [dbo].[Teacher]  WITH CHECK ADD  CONSTRAINT [FK_Teacher_College] FOREIGN KEY([Departments])
REFERENCES [dbo].[College] ([COID])
GO
ALTER TABLE [dbo].[Teacher] CHECK CONSTRAINT [FK_Teacher_College]
GO
ALTER TABLE [dbo].[Student]  WITH CHECK ADD  CONSTRAINT [CK_Student_Gender] CHECK  (([StudentGender]=(0) OR [StudentGender]=(1)))
GO
ALTER TABLE [dbo].[Student] CHECK CONSTRAINT [CK_Student_Gender]
GO
ALTER TABLE [dbo].[Teacher]  WITH CHECK ADD  CONSTRAINT [CK_Teacher_Salary] CHECK  (([TSalary]>(0)))
GO
ALTER TABLE [dbo].[Teacher] CHECK CONSTRAINT [CK_Teacher_Salary]
GO
ALTER TABLE [dbo].[Teacher]  WITH CHECK ADD  CONSTRAINT [CK_Teacher_TGender] CHECK  (([TGender]=(0) OR [TGender]=(1)))
GO
ALTER TABLE [dbo].[Teacher] CHECK CONSTRAINT [CK_Teacher_TGender]
GO
/****** Object:  StoredProcedure [dbo].[usp_getStudentScoreByPage]    Script Date: 2020/5/29 16:04:00 ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
CREATE proc [dbo].[usp_getStudentScoreByPage]
 @pageSize int =16, --每页记录条数
 @pageIndex int=1, --当前要查看第几页的记录
 @TID varchar(11) ,--教师ID
 @recordCount int output, --总的记录条数
 @pageCount int output-- 总的页数
 as 
 begin 
	select StudentID,StudentName,CName,Score,CID from
	(select  s.StudentID,s.StudentName,c.CName,sg.Score ,c.CID,rn=ROW_NUMBER() over(order by AutoID asc) from Student_Grade as sg
	inner join Student as s on s.StudentID=sg.SID
	inner join Course as c on c.CID=sg.CID
	where sg.CID in (select Course.CID from Course where Teacher= @TID)) as sc
	where sc.rn between (@pageIndex-1)*@pageSize+1 and @pageSize*@pageIndex

	--计算总的记录条数
	set @recordCount=(select count(*) from Student_Grade)

	--计算总页数
	set @pageCount=CEILING(@recordCount*1.0/@pageSize)
 end
GO
USE [master]
GO
ALTER DATABASE [EAMDatabase] SET  READ_WRITE 
GO

将访问数据库的方法抽象成一个类

因为在数据库里对数据加了一些约束，违反约束时会报错，所以对两个常用的方法多加了一次异常捕捉

using System;
using System.Collections.Generic;
using System.Configuration;
using System.Data;
using System.Data.SqlClient;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace EAM.DAL
{
    public static class SqlHelper
    {
        //从配置文件中读取数据库连接字符串
        private static readonly string conStr = ConfigurationManager.ConnectionStrings["mssql"].ConnectionString;


        public static int ExecuteNonquery(string sql, CommandType cmdType, params SqlParameter[] pms)
        {
            using (SqlConnection con = new SqlConnection(conStr))
            {
                using (SqlCommand com = new SqlCommand(sql, con))
                {
                    com.CommandType = cmdType;
                    if (pms != null)
                    {
                        com.Parameters.AddRange(pms);
                    }
                    con.Open();
                    try
                    {
                        return com.ExecuteNonQuery();
                    }
                    catch (Exception)
                    {

                        return 0;
                    }
                }
            }

        }

        public static object ExecuteScalar(string sql, CommandType cmdType, params SqlParameter[] pms)
        {
            using (SqlConnection con = new SqlConnection(conStr))
            {
                using (SqlCommand com = new SqlCommand(sql, con))
                {
                    com.CommandType = cmdType;
                    if (pms != null)
                    {
                        com.Parameters.AddRange(pms);
                    }
                    con.Open();
                    return com.ExecuteScalar();
                }
            }
        }

        public static SqlDataReader ExecuteReader(string sql, CommandType cmdType, params SqlParameter[] pms)
        {
            SqlConnection con = new SqlConnection(conStr);
            using (SqlCommand com = new SqlCommand(sql, con))
            {
                com.CommandType = cmdType;
                if (pms != null)
                {
                    com.Parameters.AddRange(pms);
                }
                try
                {
                    con.Open();
                    return com.ExecuteReader(System.Data.CommandBehavior.CloseConnection);
                }
                catch
                {
                    con.Close();
                    con.Dispose();
                    throw;
                }
            }
        }

        public static DataTable ExecuteDataTable(string sql, CommandType cmdType, params SqlParameter[] pms)
        {
            DataTable dt = new DataTable();
            using (SqlDataAdapter adapter = new SqlDataAdapter(sql, conStr))
            {
                adapter.SelectCommand.CommandType = cmdType;
                if (pms != null)
                {
                    adapter.SelectCommand.Parameters.AddRange(pms);
                }
                try
                {
                    adapter.Fill(dt);
                }
                catch (Exception)
                {
                    throw;
                }
            }
            return dt;
        }
    }
}

登录功能的实现

在这里插入图片描述
学生的
数据访问层

    /// <summary>
        /// 登录时，根据用户名查询相应的对象信息
        /// </summary>
        /// <param name="sid">用户名</param>
        /// <returns></returns>
        public Student getStudentInfoBySid(string sid)
        {
            string sql = "select * from Student where StudentID=@sid";
            SqlParameter pms = new SqlParameter("@sid", SqlDbType.VarChar, 11) { Value = sid };
            DataTable dt = SqlHelper.ExecuteDataTable(sql, CommandType.Text, pms);
            Student student = null;
            if (dt.Rows.Count > 0)
            {
            	//RowToStudent是一个方法，将一行数据转换为一个学生对象
                student = RowToStudent(dt.Rows[0]);
            }
            return student;
        }


  		private Student RowToStudent(DataRow dr)
        {
            Student student = new Student();
            student.SID = dr["StudentID"].ToString();
            student.PassWord = dr["PassWord"].ToString();
            student.SName = dr["StudentName"].ToString();
            student.SGender = (Convert.ToBoolean(dr["StudentGender"])) ? "男" : "女";
            student.Birthday = Convert.ToDateTime(dr["Birthday"]);
            student.AdmissionTime = Convert.ToDateTime(dr["AdmissionTime"]);
            student.Departments = dr["Departments"].ToString();
            student.Class = dr["Class"].ToString();
			
			//这里考虑了数据库中是否有学生的图像，有的话，显示的就是学生的图像，没有的话，就显示默认图像
            if (!dr.IsNull("Image"))
            {
                byte[] imageByte = (byte[])dr["Image"];
                MemoryStream stream = new MemoryStream(imageByte);
                student.Image = new Bitmap(stream);
            }


            return student;
        }

业务逻辑层

  /// <summary>
        /// 登录时，根据用户名查询相应的对象信息
        /// </summary>
        /// <param name="sid">用户名</param>
        /// <param name="pwd">密码</param>
        /// <param name="msg">提示信息</param>
        /// <param name="stu">学生对象</param>
        /// <returns>成功与否</returns>
        public bool getStudentInfoBySid(string sid, string pwd, out string msg,out Student stu)
        {
             stu = dal.getStudentInfoBySid(sid);
            if (stu != null)
            {
                if (stu.PassWord == MD5Encode.GetMd5(pwd))
                {
                    msg = "登录成功";
                    return true;
                }
                else
                {
                    msg = "密码错误";
                    return false;

                }
            }
            else
            {
                msg = "该用户不存在";
                return false;
            }
        }

教师的
学生和教师的登录方面的代码几乎一样
数据访问层

   /// <summary>
        /// 根据输入的用户名查询 用户
        /// </summary>
        /// <param name="ID">用户名</param>
        /// <returns>用户对象</returns>
        public Teacher GetTeacherInfo(string ID)
        {
            string sql = "select * from Teacher where TID=@Id";
            SqlParameter pms = new SqlParameter("@Id", SqlDbType.VarChar, 11) { Value = ID };
            DataTable dt = SqlHelper.ExecuteDataTable(sql, CommandType.Text, pms);
            Teacher teacher = null;
            if (dt.Rows.Count>0)
            {
                teacher = RowToTeacherInfo(dt.Rows[0]);
            }
            return teacher;
        }

        //将查到的一行数据 转换为一个对象
        private Teacher RowToTeacherInfo(DataRow dr)
        {
            Teacher tea = new Teacher();
            tea.TID = dr["TID"].ToString();
            tea.PassWord = dr["PassWord"].ToString();
            tea.TName = dr["TName"].ToString();
            tea.TGender = (Convert.ToBoolean(dr["TGender"])) ? "男" : "女";
            tea.Birthday = Convert.ToDateTime(dr["Birthday"]);
            tea.AdmissionTime = Convert.ToDateTime(dr["AdmissionTime"]);
            tea.Departments = dr["Departments"].ToString();
            tea.TSalary = Convert.ToDecimal(dr["TSalary"]);
            tea.Address = dr["Address"].ToString();

            if (!dr.IsNull("Image"))
            {
                byte[] imageByte = (byte[])dr["Image"];
                MemoryStream stream = new MemoryStream(imageByte);
                tea.Image = new Bitmap(stream);
            }


            return tea;
        }

业务逻辑层

   /// <summary>
        /// 根据用户的账号密码，判断是否登录成功
        /// </summary>
        /// <param name="id">账号</param>
        /// <param name="pwd">密码</param>
        /// <param name="msg">提示信息</param>
        /// <returns>成功与否</returns>
        public bool GetTeacherInfo(string id,string pwd,out string msg)
        {
            Teacher teacher = dal.GetTeacherInfo(id);
            if (teacher!=null)
            {
                if (teacher.PassWord==MD5Encode.GetMd5(pwd))
                {
                    msg = "登录成功";
                    return true;
                }
                else
                {
                    msg = "密码错误";
                    return false;

                }
            }
            else
            {
                msg = "该用户不存在";
                return false;
            }
        }

用户界面层

   /// <summary>
        /// 登录按钮，根据用户输入的用户名和密码，与数据库中的数据进行比对 
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void button1_Click(object sender, EventArgs e)
        {
            if (string.IsNullOrEmpty(textBox1.Text) ||string.IsNullOrEmpty(textBox2.Text))
            {
                return;
            }
            string msg;
            string id = textBox1.Text.Trim();
            string pwd = textBox2.Text.Trim();

            if (ucSwitch1.Checked)
            {
               
                TeacherBLL bll = new TeacherBLL();
                Boolean b = bll.GetTeacherInfo(id, pwd, out msg);
                if (b)
                {
                    //FrmTips.ShowTipsSuccess(this, msg);
                    //fea.Obj = bll.GetTeacher(id);
                    //FrmTeacherMain frmTeacher = new FrmTeacherMain();
                    //this.evtFt += new EventHandler(frmTeacher.SetTxt);
                    //if (this.evtFt!=null)
                    //{
                    //    this.evtFt(this, fea);

                    //    frmTeacher.ShowDialog();

                    //}
                    FrmTips.ShowTipsSuccess(this, msg);
                    this.Tag = bll.GetTeacher(id);
                    this.DialogResult = DialogResult.OK;
                }
                else
                {
                    FrmTips.ShowTipsError(this, msg);
                }
            }
            else
            {
                StudentBLL bll = new StudentBLL();
                Student stu = new Student();
                bool b = bll.getStudentInfoBySid(id, pwd, out msg,out stu);
                if (b)
                {
                    this.Tag = stu;
                    this.DialogResult = DialogResult.Yes;
                }
                else
                {
                    FrmTips.ShowTipsError(this, msg);
                }
            }
        }

全部的功能基本都是按着这三步走的，从数据访问层获取数据，再经过业务逻辑层，最后呈现到用户界面层

这个教师和学生登录功能，完全可以合并，根据用户的选项是教师还是学生，加一个判断标识，从而调用方法。尤其是登录业务逻辑层的代码，一摸一样，完全可以写为一个方法。

登录成功后，个人信息的展示

在这里插入图片描述

主函数里的代码

using EAM.Model;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace Educational_Administration_Management
{
    public static class Program
    {
        /// <summary>
        /// 应用程序的主入口点。
        /// </summary>
        [STAThread]
        static void Main()
        {
            Application.EnableVisualStyles();
            Application.SetCompatibleTextRenderingDefault(false);
            Form1 frm = new Form1();

            if (frm.ShowDialog() == DialogResult.OK)
            {
                Teacher t = frm.Tag as Teacher;

                Application.Run(new FrmTeacherMain(ref t));
            }
            else if (frm.DialogResult == DialogResult.Yes)
            {
                Student s = frm.Tag as Student;
                Application.Run(new FrmStudentMain(s));
            }

            // Application.Run(new Form1());
        }
    }
}

在上面的代码里，看到了传参时，一个加了ref关键字，另一个没加。在这里其实不用加：如果你只想在方法中改变引用参数的内容，没有必要使用Ref来修饰引用参数。如果你希望在方法中改变引用对象参数的引用(调用方法外的)，如重新初始化对象，则需要使用Ref关键字来修饰参数。在将教师方面的功能做完后，发现不用加ref，但在生成教师主窗体时传递的参数也仍保留了ref。
就这样，在数据库中可以查询到相应数据，可以登录时，在生成对应的主窗体时，将包含个人信息的对象作为参数传递过去，之后再一一赋值。

 private void UCT_Home_Load(object sender, EventArgs e)
        {
            lblAddress.Text = teacher.Address;
            lblBir.Text = teacher.Birthday.ToString("yyy/MM/dd");
            lblAdm.Text = teacher.AdmissionTime.ToString("yyy/MM/dd");
          
            lblGender.Text = teacher.TGender;
            lblID.Text = teacher.TID;
            lblMoney.Text = teacher.TSalary.ToString();
            lblName.Text = teacher.TName;

            lblDep.Text = teacher.Departments.ToString();
            CollegeBLL bll = new CollegeBLL();
            List<College> list = bll.GetColleges();
            foreach (var item in list)
            {
                if (item.COID==lblDep.Text)
                {
                    lblDep.Text = item.COName;
                    break;
                }
            }

            if (teacher.Image!=null)
            {
                UserImage.Image = teacher.Image;
            }
        }

 private void UCS_Home_Load(object sender, EventArgs e)
        {
            lblID.Text = student.SID;
            lblName.Text = student.SName;
            lblGender.Text = student.SGender;
            lblBir.Text = student.Birthday.ToString("yyy/MM/dd");
            lblAdm.Text = student.AdmissionTime.ToString("yyy/MM/dd");
            lblDep.Text = student.Departments;
            lblClass.Text = student.Class;
            lblAge.Text = (DateTime.Now.Year - student.Birthday.Year).ToString();

            List<College> colList = new CollegeBLL().GetColleges();
            foreach (var item in colList)
            {
                if (item.COID == lblDep.Text)
                {
                    lblDep.Text = item.COName;
                    break;
                }
            }

            List<Class> claList = new ClassBLL().GetClasses();
            foreach (var item in claList)
            {
                if (item.CLID == lblClass.Text)
                {
                    lblClass.Text = item.CLName;
                    break;
                }
            }

            if (student.Image != null)
            {
                UserImage.Image = student.Image;
            }
        }

教师的学生管理

在这里插入图片描述

加载该页面时的数据访问层

   /// <summary>
        /// 获得所有学生信息
        /// </summary>
        /// <returns></returns>
        public List<Student> GetAllStudents()
        {
            //string sql = "select StudentID,StudentName,StudentGender,Birthday,AdmissionTime,Departments,Class from Student";
            string sql = "select StudentID,StudentName,StudentGender,Birthday,AdmissionTime,college.COName,class.CLName from Student as student inner join Class as  class on student.Class=class.CLID inner join College as college on student.Departments=college.COID";
            DataTable dt = SqlHelper.ExecuteDataTable(sql, CommandType.Text);
            List<Student> list = null ;
            if (dt.Rows.Count>0)
            {
                list = new List<Student>();
                foreach (DataRow item in dt.Rows)
                {
                    list.Add(RowToStudentInfo(item));
                }
            }
            return list;
        }

加载该页面时的业务逻辑层

 /// <summary>
        /// 获得所有学生信息
        /// </summary>
        /// <returns></returns>
        public List<Student> GetAllStudents()
        {
            return dal.GetAllStudents();
        }

加载该页面时的用户界面层

  private void UCT_StudentManagement_Load(object sender, EventArgs e)
        {
            LoadStudentInfo();
        }
        StudentBLL bll = new StudentBLL();
        private void LoadStudentInfo()
        {

            dataGridView1.DataSource = bll.GetAllStudents();
            dataGridView1.AutoGenerateColumns = false;
             if (dataGridView1.Rows.Count>0)
            {
               
                dataGridView1.Rows[0].Selected = false;
            }
            for (int i = 8; i < dataGridView1.Columns.Count; i++)
            {
               
                dataGridView1.Columns[i].Visible = false;
            }
            dataGridView1.Columns[1].Visible = false;
        }

增加学生的数据访问层

   /// <summary>
        /// 添加学生
        /// </summary>
        /// <param name="student">学生对象</param>
        /// <returns>所影响的行数</returns>
        public int AddStudentInfo(Student student)
        {
            string sql = "insert into Student (StudentID,PassWord,StudentName,StudentGender,Birthday,AdmissionTime,Departments,Class,Image) values (@SID,@PWD,@SName,@SGender,@Birthday,@AdmissionTime,@Departments,@Class,@Image)";

            SqlParameter[] pms = new SqlParameter[]
            {
                new SqlParameter("@SID", SqlDbType.VarChar,11){ Value=student.SID},
                new SqlParameter("@PWD", SqlDbType.VarChar,50){ Value=student.PassWord},
                new SqlParameter("@SName", SqlDbType.NVarChar,10){ Value=student.SName},
                new SqlParameter("@SGender", SqlDbType.Bit){Value=student.SGender=="男"?true:false},
                new SqlParameter("@Birthday", SqlDbType.DateTime){Value=student.Birthday},
                new SqlParameter("@AdmissionTime", SqlDbType.DateTime){Value=student.AdmissionTime},
                new SqlParameter("@Departments", SqlDbType.VarChar,11){Value=student.Departments},
                new SqlParameter("@Class", SqlDbType.VarChar,11){ Value=student.Class},
                new SqlParameter("@Image", SqlDbType.Image){Value=DBNull.Value}
            };


            try
            {
                return SqlHelper.ExecuteNonquery(sql, CommandType.Text, pms);
            }
            catch (Exception)
            {

                return 0;
            }
        }

增加学生时的业务逻辑层

 /// <summary>
        /// 添加学生
        /// </summary>
        /// <param name="student">学生对象</param>
        /// <returns>成功与否</returns>
        public bool AddStudentInfo(Student student)
        {
            return dal.AddStudentInfo(student)>0;
        }

增加学生的用户界面层

 //添加学生
        private void btnAdd_Click(object sender, EventArgs e)
        {
            FrmAddStudent frmAdd = new FrmAddStudent();
            frmAdd.FormClosed += new FormClosedEventHandler(frmAdd_FormClosed);
            frmAdd.ShowDialog();
        }

        private void frmAdd_FormClosed(object sender, FormClosedEventArgs e)
        {
            LoadStudentInfo();
        }

删除学生的数据访问层

   /// <summary>
        /// 根据学号，删除相应的学生
        /// </summary>
        /// <param name="sid">学号</param>
        /// <returns>所影响的行数</returns>
        public int DeleteStudentInfo(string sid)
        {
            string sql = "delete from Student Where StudentID=" + sid;
            return SqlHelper.ExecuteNonquery(sql, CommandType.Text);
        }

删除学生的业务逻辑层

  /// <summary>
        /// 根据学号，删除相应的学生
        /// </summary>
        /// <param name="sid">学号</param>
        /// <returns>所影响的行数</returns>
        public bool DeleteStudentInfo(string sid)
        {
            return dal.DeleteStudentInfo(sid) > 0;
        }

删除学生的用户界面层

 //删除学生
        private void btnDelete_Click(object sender, EventArgs e)
        {
            if (dataGridView1.SelectedRows.Count>0)
            {
                string sid = dataGridView1.SelectedRows[0].Cells[0].Value.ToString();

                StudentBLL bll = new StudentBLL();
                string msg = bll.DeleteStudentInfo(sid)?"删除成功":"删除失败";
                MessageBox.Show(msg);
                LoadStudentInfo();
            }
            else
            {
                MessageBox.Show("请选择要删除的行");
            }

        }

修改学生的数据访问层

   /// <summary>
        /// 修改学生信息
        /// </summary>
        /// <param name="student">学生对象</param>
        /// <returns>所影响的行数</returns>
        public int UpdateStudentInfo(Student student)
        {
            string sql = "Update Student set StudentName=@SName,StudentGender=@SGender,Birthday=@Bir,AdmissionTime=@Admi,Departments=@Depart,Class=@Cla,Image=@Image Where StudentID=@SID";

            SqlParameter[] pms = new SqlParameter[]
            {
                new SqlParameter("@SID", SqlDbType.VarChar,11){ Value=student.SID},
                //new SqlParameter("@PWD", SqlDbType.VarChar,50){ Value=student.PassWord},
                new SqlParameter("@SName", SqlDbType.NVarChar,10){ Value=student.SName},
                new SqlParameter("@SGender", SqlDbType.Bit){Value=student.SGender=="男"?true:false},
                new SqlParameter("@Bir", SqlDbType.DateTime){Value=student.Birthday},
                new SqlParameter("@Admi", SqlDbType.DateTime){Value=student.AdmissionTime},
                new SqlParameter("@Depart", SqlDbType.VarChar,11){Value=student.Departments},
                new SqlParameter("@Cla", SqlDbType.VarChar,11){ Value=student.Class},
                new SqlParameter("@Image", SqlDbType.Image){Value=DBNull.Value}
            };
            //List<SqlParameter> list = new List<SqlParameter>();
            //list.AddRange(pms);

         
            if (student.Image!=null)
            {
                pms[7].Value = student.Image;
            }

            try
            {
                return SqlHelper.ExecuteNonquery(sql, CommandType.Text, pms);
            }
            catch (Exception)
            {

                return 0;
            }
        }

修改学生的业务逻辑层

  /// <summary>
        /// 修改学生信息
        /// </summary>
        /// <param name="student">学生对象</param>
        /// <returns>成功与否</returns>
        public bool UpdateStudentInfo(Student student)
        {
            return dal.UpdateStudentInfo(student) > 0;
        }

修改学生的用户界面层

  //修改学生
        public event EventHandler evtFes;
        FrmEventArgs fea = new FrmEventArgs();
        private void btnEdit_Click(object sender, EventArgs e)
        {
            if (dataGridView1.SelectedRows.Count>0)
            {
                string sid = dataGridView1.SelectedRows[0].Cells[0].Value.ToString();

                StudentBLL bll = new StudentBLL();
                fea.Obj = bll.GetStudentBySid(sid);

                FrmEditStudent frmEdit = new FrmEditStudent();
                this.evtFes += new EventHandler(frmEdit.SetTxt);
                if (this.evtFes!=null)
                {
                    this.evtFes(this, fea);
                    frmEdit.FormClosed += new FormClosedEventHandler(frmAdd_FormClosed);
                    frmEdit.ShowDialog();
                }
            }
            else
            {
                MessageBox.Show("请选中要修改的学生");
            }
        }

查询学生的数据访问层

   /// <summary>
        /// 根据查询条件，查找相应的学生
        /// </summary>
        /// <param name="info">条件</param>
        /// <returns>查到的学生</returns>
        public List<Student> GetStudentsByInfo(string info)
        {
            List<Student> list = new List<Student>();
            string sql = " select StudentID, StudentName, StudentGender, Birthday, AdmissionTime, college.COName,class.CLName from Student as student inner join Class as  class on student.Class=class.CLID inner join College as college on student.Departments=college.COID Where student.StudentID like @SID or student.StudentName like @SName";

            SqlParameter[] pms = new SqlParameter[]
            {
                new SqlParameter("@SID","%"+info+"%"),
                new SqlParameter("@SName","%"+info+"%")
            };

            DataTable dt = SqlHelper.ExecuteDataTable(sql, CommandType.Text, pms);
            if (dt.Rows.Count>0)
            {
                foreach (DataRow dr in dt.Rows)
                {
                    list.Add(RowToStudentInfo(dr));
                }
            }
            return list;
        }

查询学生的业务逻辑层

   /// <summary>
        /// 根据查询条件，查找相应的学生
        /// </summary>
        /// <param name="info">条件</param>
        /// <returns>查到的学生</returns>
        public List<Student> GetStudentsByInfo(string info)
        {
            return dal.GetStudentsByInfo(info);
        }

查询学生的用户界面层

 //查询学生
        private void btnSearch_Click(object sender, EventArgs e)
        {
            string info = textBox1.Text;
            StudentBLL bll = new StudentBLL();

            List<Student> list = bll.GetStudentsByInfo(info);
            if (list.Count>0)
            {
                dataGridView1.DataSource = list;
            }
            else
            {
                MessageBox.Show("没有查询到相应的学生");
            }
        }

教师的课程管理

在这里插入图片描述

加载自己开设课程的数据访问层

  /// <summary>
        /// 根据教师ID，查询教师开的课程
        /// </summary>
        /// <param name="TID">教师ID</param>
        /// <returns></returns>
        public List<Course> GetCourses(string TID)
        {
            string sql = "select * from Course where Teacher=" + TID;
            List<Course> list = new List<Course>();
            DataTable dt = SqlHelper.ExecuteDataTable(sql, CommandType.Text);
            if (dt.Rows.Count>0)
            {
                foreach (DataRow dr in dt.Rows)
                {

                    list.Add(RowToCourse(dr));
                }
            }
            return list;

        }

加载自己开设课程的业务逻辑层

 /// <summary>
        /// 根据教师ID，查询教师开的课程
        /// </summary>
        /// <param name="TID">教师ID</param>
        /// <returns></returns>
        public List<Course> GetCourses(string TID)
        {
            return dal.GetCourses(TID);
        }

加载自己开设课程的用户界面层

 //加载课程信息
        private void LoadCourseInfo()
        {
            CourseBLL bll = new CourseBLL();
            dataGridView1.DataSource = bll.GetCourses(teacher.TID);
        }

增加课程的数据访问层

  /// <summary>
        /// 添加课程
        /// </summary>
        /// <param name="course">课程对象</param>
        /// <returns></returns>
        public int AddCourse(Course course)
        {
            string sql = "insert into Course values(@CID,@CName,@Dep,@Teac)";
            SqlParameter[] pms = new SqlParameter[]
            {
                new SqlParameter("@CID", course.CID),
                new SqlParameter("@CName",course.CName),
                new SqlParameter("@Dep",course.Departments),
                new SqlParameter("@Teac",course.CTeacher)
        };

            try
            {
                return SqlHelper.ExecuteNonquery(sql, CommandType.Text, pms);
            }
            catch (Exception)
            {

                return 0;

            }
        }

增加课程的业务逻辑层

 /// <summary>
        /// 添加课程
        /// </summary>
        /// <param name="course">课程对象</param>
        /// <returns></returns>
        public bool AddCourse(Course course)
        {
            return dal.AddCourse(course) > 0;
        }

增加课程的用户界面层

  //添加课程
        private void ucBtnAdd_BtnClick(object sender, EventArgs e)
        {
            if (!Check.isCourse(textBox1.Text))
            {
                MessageBox.Show("课程号错误");
                return;
            }

            string cid = textBox1.Text;
            string cname = textBox2.Text;

            Course course = new Course()
            {
                CID=cid,
                CName=cname,
                Departments=teacher.Departments,
                CTeacher=teacher.TID
            };
            CourseBLL bll = new CourseBLL();
           if (bll.AddCourse(course))
            {
                MessageBox.Show("添加成功");
                LoadCourseInfo();
                textBox1.Text = "";
                textBox2.Text = "";
            }
           else
            {
                MessageBox.Show("添加失败");
            }

        }

删除课程的数据访问层

  /// <summary>
        /// 根据课程号，删除课程
        /// </summary>
        /// <param name="CID">课程号</param>
        /// <returns></returns>
        public int DeleteCourse(string CID)
        {
            string sql = "delete from Course Where CID=" + CID;
            return SqlHelper.ExecuteNonquery(sql, CommandType.Text);
        }

删除课程的业务逻辑层

  /// <summary>
        /// 根据课程号，删除课程
        /// </summary>
        /// <param name="CID">课程号</param>
        /// <returns></returns>
        public bool DeleteCourse(string CID)
        {
            return dal.DeleteCourse(CID) > 0;
        }

删除课程的用户界面层

 //删除课程
        private void ucBtnDelete_BtnClick(object sender, EventArgs e)
        {
            if (dataGridView1.SelectedRows.Count>0)
            {
                string sid = dataGridView1.SelectedRows[0].Cells[0].Value.ToString();
                CourseBLL bll = new CourseBLL();
                string msg = bll.DeleteCourse(sid) ? "删除成功" : "删除失败";
                MessageBox.Show(msg);
                LoadCourseInfo();
            }
            else
            {
                MessageBox.Show("请选中要删除的行");
            }
        }

加载选修自己课程的学生信息的数据访问层

 /// <summary>
        /// 获得教师所教授的学生成绩表的信息
        /// </summary>
        /// <param name="tid">教师ID</param>
        /// <param name="pageCount"></param>
        /// <param name="recordCount"></param>
        /// <returns></returns>
        public DataTable GetScores(string tid,out string pageCount,out string recordCount,int pageIndex,int pageSize)
        {
            SqlParameter[] pms = new SqlParameter[]
           {
                new SqlParameter("@TID", SqlDbType.VarChar,11){Value=tid},
                new SqlParameter("@pageIndex", SqlDbType.Int){Value=pageIndex},
                new SqlParameter("@pageSize", SqlDbType.Int){Value=pageSize},
                new SqlParameter("@pageCount", SqlDbType.Int){Direction= ParameterDirection.Output},
                new SqlParameter("@recordCount", SqlDbType.Int){Direction= ParameterDirection.Output}
           };
            DataTable dt = SqlHelper.ExecuteDataTable("usp_getStudentScoreByPage", CommandType.StoredProcedure,pms);

            
            pageCount = pms[3].Value.ToString();
            recordCount = pms[4].Value.ToString();

            return dt;
        }

加载选修自己课程的学生信息的业务逻辑层

  /// <summary>
        /// 获得教师所教授的学生的成绩
        /// </summary>
        /// <param name="tid"></param>
        /// <param name="pageCount"></param>
        /// <param name="recordCount"></param>
        /// <returns></returns>
        public DataTable GetScores(string tid, out string pageCount, out string recordCount,int pageIndex,int pageSize)
        {
            return dal.GetScores(tid, out pageCount, out recordCount,pageIndex,pageSize);
        }

加载选修自己课程的学生信息的用户界面层

  int pageIndex = 1, pageSize = 16;
        string pageCount;
        string recordCount;
        //加载学生成绩信息
        private void LoadScoreInfo()
        {
            ScoreBLL bll = new ScoreBLL();
           
           
            dataGridView2.DataSource = bll.GetScores(teacher.TID,out pageCount,out recordCount,pageIndex,pageSize);

            label1.Text = "共有" + pageCount + "页，共有" + recordCount + "条记录";

        }

    //上一页
        private void ucBtnExt1_BtnClick(object sender, EventArgs e)
        {
            pageIndex--;
            if (pageIndex<1)
            {
                pageIndex = 1;
            }
            label2.Text = "当前为第" + pageIndex + "页";
            LoadScoreInfo();
        }

        //下一页
        private void ucBtnExt2_BtnClick(object sender, EventArgs e)
        {
            pageIndex++;
            if (pageIndex>Convert.ToInt32(pageCount))
            {
                pageIndex = Convert.ToInt32(pageCount);
            }
            label2.Text = "当前为第" + pageIndex + "页";
            LoadScoreInfo();
        }

修改成绩的数据访问层

  /// <summary>
        /// 更新学生成绩
        /// </summary>
        /// <param name="score">成绩</param>
        /// <param name="sid">学生id</param>
        /// <returns></returns>
        public int UpdateScore(int score,string sid,string cid)
        {
            string sql = "update Student_Grade set Score=@score where SID=" + sid+" and CID ="+cid;

            SqlParameter pms = new SqlParameter("@score", score);
            return SqlHelper.ExecuteNonquery(sql, CommandType.Text, pms);
        }

修改成绩的业务逻辑层

   /// <summary>
        /// 更新学生成绩
        /// </summary>
        /// <param name="score">成绩</param>
        /// <param name="sid">学生id</param>
        /// <returns></returns>
        public bool UpdateScore(int score, string sid,string cid)
        {
            return dal.UpdateScore(score, sid,cid) > 0;
        }

修改成绩的用户界面层

 private void dataGridView2_DataError(object sender, DataGridViewDataErrorEventArgs e)
        {
            MessageBox.Show("格式不正确,请输入整数");
            dataGridView2.CancelEdit();
        }

        private void dataGridView2_CellEndEdit(object sender, DataGridViewCellEventArgs e)
        {

            string sid="";
            string cid="";
            int score=0;
            try
            {
                 sid = dataGridView2.Rows[e.RowIndex].Cells[0].Value.ToString();
                 cid = dataGridView2.Rows[e.RowIndex].Cells[4].Value.ToString();
                 score = Convert.ToInt32(dataGridView2.Rows[e.RowIndex].Cells[3].Value);
            }
            catch (Exception)
            {
                MessageBox.Show("录入失败");
                return;
            }

            //这个判断看起来，有些智障，不过 就先这样吧
            if (score < 0 || score > 100)
            {
                MessageBox.Show("输入错误");
                return;
            }

            ScoreBLL bll = new ScoreBLL();
            if (!bll.UpdateScore(score,sid,cid))
            {

                MessageBox.Show("录入失败");
            }
        }

修改个人信息

在这里插入图片描述

修改个人信息的数据访问层

/// <summary>
        /// 修改教师信息
        /// </summary>
        /// <param name="t"></param>
        /// <returns></returns>
        public int EditTeacher(Teacher t)
        {
            string sql = "update Teacher set TName=@name,TGender=@gender,Birthday=@bir,AdmissionTime=@adm,Departments=@depart,TSalary=@salary,Image=@image,Address=@add where TID=@ID";
            byte[] buffer;
            using(MemoryStream ms=new MemoryStream())
            {
                t.Image.Save(ms, System.Drawing.Imaging.ImageFormat.Bmp);
                buffer = ms.GetBuffer();
            }
            SqlParameter[] pms = new SqlParameter[]
            {
                new SqlParameter("@ID",t.TID),
                new SqlParameter("@name",t.TName),
                new SqlParameter("@gender", SqlDbType.Bit){Value=t.TGender=="男"?true:false},
                new SqlParameter("@bir", SqlDbType.DateTime){Value=t.Birthday},
                new SqlParameter("@adm", SqlDbType.Date){Value=t.AdmissionTime},
                new SqlParameter("@depart", t.Departments),
                new SqlParameter("@salary",t.TSalary),
                new SqlParameter("@add",t.Address),
                new SqlParameter("@image", SqlDbType.Image){Value=buffer}
            };

            try
            {
                return SqlHelper.ExecuteNonquery(sql, CommandType.Text, pms);
            }
            catch (Exception)
            {

                return 0;
            }
        }

修改信息的业务逻辑层

  /// <summary>
        /// 修改教师信息
        /// </summary>
        /// <param name="t"></param>
        /// <returns></returns>
        public bool EditTeacher(Teacher t)
        {
            return dal.EditTeacher(t)>0;
        }

修改信息的用户界面层

    //确定修改
        private void ucBtnSave_BtnClick(object sender, EventArgs e)
        {
            if (!Check.isTeacherID(txtTID.Text))
            {
                MessageBox.Show("工号不正确");
                return;
            }

            try
            {
                teacher.TID = txtTID.Text;
                teacher.TName = txtName.Text;
                teacher.Address = txtAddress.Text;
                teacher.TSalary = Convert.ToDecimal(txtTSalary.Text);
                teacher.TGender = cmbGender.Text;
                teacher.Departments = cmbDepart.SelectedValue.ToString();
                teacher.Birthday = Convert.ToDateTime(dtpBir.Value.ToString("yyy/MM/dd"));
                teacher.AdmissionTime = Convert.ToDateTime(dtpAdmission.Value.ToString("yyy/MM/dd"));

                teacher.Image = (Bitmap)pictureBox1.Image;
                TeacherBLL bll = new TeacherBLL();
                string msg = bll.EditTeacher(teacher) ? "修改成功" : "修改失败";
                MessageBox.Show(msg);

                LoadTeacherInfo();
            }
            catch (Exception)
            {
                MessageBox.Show("修改失败");
            }
        }

修改密码的数据访问层

 /// <summary>
        /// 修改密码
        /// </summary>
        /// <param name="pwd">新密码</param>
        /// <param name="id">教师ID</param>
        /// <returns></returns>
        public int EditPwd(string pwd,string id)
        {
            string sql = "update Teacher set PassWord=@pwd where TID=" + id;
            SqlParameter pms = new SqlParameter("@pwd", pwd);
            return SqlHelper.ExecuteNonquery(sql, CommandType.Text, pms);
        }

修改密码的业务逻辑层

  /// <summary>
        /// 修改密码
        /// </summary>
        /// <param name="pwd">新密码</param>
        /// <param name="id">教师ID</param>
        /// <returns></returns>
        public bool EditPwd(string pwd, string id)
        {
            return dal.EditPwd(pwd, id)>0;
        }

修改密码的用户界面层

   private void ucBtnChangePwd_BtnClick(object sender, EventArgs e)
        {
            FrmInputs frm = new FrmInputs("修改密码",
                  new string[] { "旧密码", "新密码", "确定密码" },
                  new Dictionary<string, HZH_Controls.TextInputType>() { },
                 new Dictionary<string, string>() { },
                 new Dictionary<string, KeyBoardType>() { { "旧密码", KeyBoardType.UCKeyBorderAll_EN }, { "新密码", KeyBoardType.UCKeyBorderAll_EN } },
                 new List<string>() { "旧密码", "新密码", "确定密码" });
            frm.ShowDialog(this);
            if (frm.DialogResult== DialogResult.OK)
            {
                string oldPwd = frm.Values[0];
                string newPwd = frm.Values[1];
                string comPwd = frm.Values[2];
                if (newPwd!=comPwd)
                {
                    MessageBox.Show("两次密码不一致");
                    return;
                }

               if (!Check.isPwd(newPwd))
                {
                    MessageBox.Show("密码最少6位，包括至少1个大写字母，1个小写字母，1个数字，1个特殊字符");
                    return;
                }

                if (MD5Encode.GetMd5(oldPwd)==teacher.PassWord)
                {
                    TeacherBLL bll = new TeacherBLL();
                    string msg = bll.EditPwd(MD5Encode.GetMd5(newPwd), teacher.TID)?"修改成功":"修改失败";
                    MessageBox.Show(msg);
                }
                else
                {
                    MessageBox.Show("原密码错误");
                }
            }
        }

学生的课程管理

在这里插入图片描述

加载学院开设课程，学生已选课程，学生选课、退课的数据访问层

 /// <summary>
        /// 学生选课时，获得所有课程
        /// </summary>
        /// <returns></returns>
        public List<Course> getCourse()
        {
            string sql = "select * from Course";
            List<Course> list = new List<Course>();

            DataTable dt = SqlHelper.ExecuteDataTable(sql, CommandType.Text);
            if (dt.Rows.Count>0)
            {
                foreach (DataRow item in dt.Rows)
                {
                    list.Add(RowToCourse(item));
                }
            }
            return list;
        }


        /// <summary>
        /// 根据学生学号，查询学生的课程
        /// </summary>
        /// <param name="sid"></param>
        /// <returns></returns>
        public List<Course> getMyCourse(string sid)
        {
            string sql = "select  c.CID,c.CName from Student_Grade as s inner join Course as c on s.CID = c.CID where s.SID = " + sid;
            List<Course> list = new List<Course>();
            using(SqlDataReader reader=SqlHelper.ExecuteReader(sql, CommandType.Text))
            {
                if(reader.HasRows)
                {
                    while(reader.Read())
                    {
                        Course course = new Course();
                        course.CID = reader.GetString(0);
                        course.CName = reader.GetString(1);
                        list.Add(course);
                    }
                }
            }
            return list;
        }

        /// <summary>
        /// 学生选课
        /// </summary>
        /// <param name="sid"></param>
        /// <param name="cid"></param>
        /// <returns></returns>
        public int AddStuCourse(string sid,string cid)
        {
            string sql = "insert into Student_Grade (SID,CID) values (@sid,@cid)";
            SqlParameter[] pms = new SqlParameter[]
            {
                new SqlParameter("@sid",sid),
                new SqlParameter("@cid",cid)
            };
            return SqlHelper.ExecuteNonquery(sql, CommandType.Text, pms);
        }

        /// <summary>
        /// 学生删除课程
        /// </summary>
        /// <param name="sid"></param>
        /// <param name="cid"></param>
        /// <returns></returns>
        public int DeleteStuCourse(string sid,string cid)
        {
            string sql = "delete from Student_Grade where SID=@sid and CID=@cid";
            SqlParameter[] pms = new SqlParameter[]
           {
                new SqlParameter("@sid",sid),
                new SqlParameter("@cid",cid)
           };
            return SqlHelper.ExecuteNonquery(sql, CommandType.Text, pms);
        }

加载学院开设课程，学生已选课程，学生选课、退课的业务逻辑层

 /// <summary>
        /// 学生选课时，获得所有课程
        /// </summary>
        /// <returns></returns>
        public List<Course> getCourse()
        {
            return dal.getCourse();
        }

        /// <summary>
        /// 根据学生学号，查询学生的课程
        /// </summary>
        /// <param name="sid"></param>
        /// <returns></returns>
        public List<Course> getMyCourse(string sid)
        {
            return dal.getMyCourse(sid);
        }

        /// <summary>
        /// 学生选课
        /// </summary>
        /// <param name="sid"></param>
        /// <param name="cid"></param>
        /// <returns></returns>
        public bool AddStuCourse(string sid, string cid)
        {
            return dal.AddStuCourse(sid, cid) > 0;
        }

        /// <summary>
        /// 学生删除课程
        /// </summary>
        /// <param name="sid"></param>
        /// <param name="cid"></param>
        /// <returns></returns>
        public bool DeleteStuCourse(string sid, string cid)
        {
            return dal.DeleteStuCourse(sid, cid) > 0;
        }

加载学院开设课程，学生已选课程，学生选课、退课的用户界面层

  private void LoadMyCourse()
        {
            CourseBLL bll = new CourseBLL();
            List<Course> list = bll.getMyCourse(sid);
            dataGridView2.DataSource = list;
        }



        private void LoadCourse()
        {
            CourseBLL bll = new CourseBLL();
            List<Course> list = bll.getCourse();
            dataGridView1.DataSource = list;
        }

        private void dataGridView1_CellMouseDoubleClick(object sender, DataGridViewCellMouseEventArgs e)
        {
            if(true)
            {
                string cid = dataGridView1.Rows[e.RowIndex].Cells[0].Value.ToString();
                CourseBLL bll = new CourseBLL();
                bool b = bll.AddStuCourse(sid, cid);
                if (b)
                {
                    MessageBox.Show("选课成功");
                    LoadMyCourse();
                }
                else
                {
                    MessageBox.Show("选课失败");
                }
            }
        }

        private void dataGridView2_CellMouseDoubleClick(object sender, DataGridViewCellMouseEventArgs e)
        {
            if (true)
            {
                string cid = dataGridView2.Rows[e.RowIndex].Cells[0].Value.ToString();
                CourseBLL bll = new CourseBLL();
                bool b = bll.DeleteStuCourse(sid, cid);
                if (b)
                {
                    MessageBox.Show("退课成功");
                    LoadMyCourse();
                }
                else
                {
                    MessageBox.Show("退课失败");
                }
            }
        }

学生成绩查询

在这里插入图片描述

查询成绩的数据访问层

 /// <summary>
        /// 学生查看自己的成绩
        /// </summary>
        /// <param name="sid">学生学号</param>
        /// <returns></returns>
        public List<Score> getScores(string sid)
        {
            string sql = "select CName,Score,TName from Student_Grade inner join Course on Course.CID = Student_Grade.CID inner join Teacher on Course.Teacher = Teacher.TID where SID = "+sid;
            List<Score> list = new List<Score>();

            using(SqlDataReader reader=SqlHelper.ExecuteReader(sql, CommandType.Text))
            {
                if (reader.HasRows)
                {
                    while(reader.Read())
                    {
                        Score score = new Score();
                        score.CID = reader.GetString(0);                        
                       score.Grade = reader.IsDBNull(1) ? null :(double?) reader.GetDouble(1);
                        score.SID = reader.GetString(2);
                        list.Add(score);
                    }
                }
            }
            return list;
        }

查询成绩的业务逻辑层

   /// <summary>
        /// 学生查看自己的成绩
        /// </summary>
        /// <param name="sid">学生学号</param>
        /// <returns></returns>
        public List<Score> getScores(string sid)
        {
            return dal.getScores(sid);
        }

查询成绩的用户界面层

 private void LoadChart()
        {
            ScoreBLL bll = new ScoreBLL();
            List<Score> list = bll.getScores(sid);

            List<string> courseList = new List<string>();
            List<double> scoreList = new List<double>();

            foreach (var item in list)
            {
               
                if (item.Grade!=null)
                {
                    scoreList.Add(Convert.ToDouble(item.Grade));
                    courseList.Add(item.CID);
                }               
            }
            chart1.ChartAreas[0].AxisX.Title = "课程";
            chart1.ChartAreas[0].AxisY.Title = "成绩";

            chart1.ChartAreas[0].AxisX.LabelStyle.Font = new Font("微软雅黑", 10, FontStyle.Bold);
            chart1.ChartAreas[0].AxisY.LabelStyle.Font = new Font("微软雅黑", 10, FontStyle.Bold);
            chart1.Series[0].Points.DataBindXY(courseList, scoreList);
           
        }

        private void LoadScore()
        {
            List<DataGridViewColumnEntity> lstCulumns = new List<DataGridViewColumnEntity>();
            lstCulumns.Add(new DataGridViewColumnEntity() { DataField = "CID", HeadText = "课程名", Width = 70, WidthType = SizeType.Percent });
            lstCulumns.Add(new DataGridViewColumnEntity() { DataField = "Grade", HeadText = "分数", Width = 70, WidthType = SizeType.Percent, Format = (a) => { return ((double?)a) == null ? "暂无成绩" : a.ToString(); } });
            lstCulumns.Add(new DataGridViewColumnEntity() { DataField = "SID", HeadText = "教师", Width = 50, WidthType = SizeType.Percent });
            this.ucDataGridView1.Columns = lstCulumns;
            this.ucDataGridView1.IsShowCheckBox = true;
            this.ucDataGridView1.DataSource = new ScoreBLL().getScores(sid);
            this.ucDataGridView1.First();
        }

学生修改个人信息

在这里插入图片描述

修改个人信息与密码的数据访问层

  /// <summary>
        /// 学生修改个人信息
        /// </summary>
        /// <param name="student"></param>
        /// <returns></returns>
        public int EditStudent(Student student)
        {
            string sql = "update Student set StudentName=@name,StudentGender=@gender,Birthday=@bir,AdmissionTime=@adm,Departments=@depart,Class=@class,Image=@image where StudentID=@ID";

            byte[] buffer;
            using (MemoryStream ms = new MemoryStream())
            {
                student.Image.Save(ms, System.Drawing.Imaging.ImageFormat.Bmp);
                buffer = ms.GetBuffer();
            }

            SqlParameter[] pms = new SqlParameter[]
            {
                new SqlParameter("@ID",student.SID),
                new SqlParameter("@name",student.SName),
                new SqlParameter("@gender", SqlDbType.Bit){ Value=student.SGender=="男"?true:false},
                new SqlParameter("@bir",student.Birthday),
                new SqlParameter("@adm", student.AdmissionTime),
                new SqlParameter("@depart",student.Departments),
                new SqlParameter("@class",student.Class),
                new SqlParameter("@image", SqlDbType.Image){Value=buffer}
            };
            try
            {
                return SqlHelper.ExecuteNonquery(sql, CommandType.Text, pms);
            }
            catch (Exception)
            {

                return 0;
            }
        }

        /// <summary>
        /// 学生修改密码
        /// </summary>
        /// <param name="pwd"></param>
        /// <param name="id"></param>
        /// <returns></returns>
        public int EditPwd(string pwd,string id)
        {
            string sql = "update Student set PassWord=@pwd where StudentID=" + id;
            SqlParameter pms = new SqlParameter("@pwd", pwd);
            return SqlHelper.ExecuteNonquery(sql, CommandType.Text, pms);
        }

学生修改个人信息的业务逻辑层

 /// <summary>
        /// 学生修改个人信息
        /// </summary>
        /// <param name="student"></param>
        /// <returns></returns>
        public bool EditStudent(Student student)
        {
            return dal.EditStudent(student) > 0;
        }


        /// <summary>
        /// 学生修改密码
        /// </summary>
        /// <param name="pwd"></param>
        /// <param name="id"></param>
        /// <returns></returns>
        public bool EditPwd(string pwd, string id)
        {
            return dal.EditPwd(pwd, id) > 0;
        }

修改个人信息的用户界面层

  private void ucBtnSave_BtnClick(object sender, EventArgs e)
        {
            if (!Check.isStudentID(txtTID.Text))
            {
                MessageBox.Show("学号不正确");
                return;
            }

            try
            {
                student.SID = txtTID.Text;
                student.SName = txtName.Text;


                student.SGender = cmbGender.Text;
                student.Departments = cmbDepart.SelectedValue.ToString();
                student.Class = cmbClass.SelectedValue.ToString();
                student.Birthday = Convert.ToDateTime(dtpBir.Value.ToString("yyy/MM/dd"));
                student.AdmissionTime = Convert.ToDateTime(dtpAdmission.Value.ToString("yyy/MM/dd"));

                student.Image = (Bitmap)pictureBox1.Image;
                StudentBLL bll = new StudentBLL();
                string msg = bll.EditStudent(student) ? "修改成功" : "修改失败";
                MessageBox.Show(msg);

                LoadStudentInfo();
            }
            catch (Exception)
            {
                MessageBox.Show("修改失败");
            }
        }

        private void ucBtnChangePwd_BtnClick(object sender, EventArgs e)
        {
            FrmInputs frm = new FrmInputs("修改密码",
                 new string[] { "旧密码", "新密码", "确定密码" },
                 new Dictionary<string, HZH_Controls.TextInputType>() { },
                new Dictionary<string, string>() { },
                new Dictionary<string, KeyBoardType>() { { "旧密码", KeyBoardType.UCKeyBorderAll_EN }, { "新密码", KeyBoardType.UCKeyBorderAll_EN } },
                new List<string>() { "旧密码", "新密码", "确定密码" });
            frm.ShowDialog(this);
            if (frm.DialogResult == DialogResult.OK)
            {
                string oldPwd = frm.Values[0];
                string newPwd = frm.Values[1];
                string comPwd = frm.Values[2];
                if (newPwd != comPwd)
                {
                    MessageBox.Show("两次密码不一致");
                    return;
                }
                 if (!Check.isPwd(newPwd))
                {
                    MessageBox.Show("密码最少6位，包括至少1个大写字母，1个小写字母，1个数字，1个特殊字符");
                    return;
                }
                if (MD5Encode.GetMd5(oldPwd) == student.PassWord)
                {
                    StudentBLL bll = new StudentBLL();
                    string msg = bll.EditPwd(MD5Encode.GetMd5(newPwd), student.SID) ? "修改成功" : "修改失败";
                    MessageBox.Show(msg);
                }
                else
                {
                    MessageBox.Show("原密码错误");
                }
            }
        }

截止到现在，B站上的作业演示视频播放量超过了5000，收藏人数过百，点赞即将过百。这个之前根本就没有想到过。现在的网友太热情了，为了回馈热情的网友，在期末考试安全通过后，把未做完的那个B/S结构的给安排上。

标签：return,string,展示,数据库,作业,student,GO,new,SqlParameter
来源： https://blog.csdn.net/Cheng_XZ/article/details/106427482

数据库大作业代码展示

首先是数据库方面的代码

将访问数据库的方法抽象成一个类

登录功能的实现

登录成功后，个人信息的展示

主函数里的代码

教师的学生管理

加载该页面时的数据访问层

加载该页面时的业务逻辑层

加载该页面时的用户界面层

增加学生的数据访问层

增加学生时的业务逻辑层

增加学生的用户界面层

删除学生的数据访问层

删除学生的业务逻辑层

删除学生的用户界面层

修改学生的数据访问层

修改学生的业务逻辑层

修改学生的用户界面层

查询学生的数据访问层

查询学生的业务逻辑层

查询学生的用户界面层

教师的课程管理

加载自己开设课程的数据访问层

加载自己开设课程的业务逻辑层

加载自己开设课程的用户界面层

增加课程的数据访问层

增加课程的业务逻辑层

增加课程的用户界面层

删除课程的数据访问层

删除课程的业务逻辑层

删除课程的用户界面层

加载选修自己课程的学生信息的数据访问层

加载选修自己课程的学生信息的业务逻辑层

加载选修自己课程的学生信息的用户界面层

查看成绩的上一页、下一页

修改成绩的数据访问层

修改成绩的业务逻辑层

修改成绩的用户界面层

修改个人信息

修改个人信息的数据访问层

修改信息的业务逻辑层

修改信息的用户界面层

修改密码的数据访问层

修改密码的业务逻辑层

修改密码的用户界面层

学生的课程管理

加载学院开设课程，学生已选课程，学生选课、退课的数据访问层

加载学院开设课程，学生已选课程，学生选课、退课的业务逻辑层

加载学院开设课程，学生已选课程，学生选课、退课的用户界面层

学生成绩查询

查询成绩的数据访问层

查询成绩的业务逻辑层

查询成绩的用户界面层

学生修改个人信息

修改个人信息与密码的数据访问层

学生修改个人信息的业务逻辑层

修改个人信息的用户界面层