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ADO.Net笔记整理（一）

2019-04-06 16:47:37 作者：互联网

几次装机，Notes已烟消云散，近日因为Node.js死活搞不定，无奈装机，备份好的东东，没想到磁盘扇区出现异常，可能是PE启动盘的病毒，只好将磁盘全部重新分区，恢复数据也懒得恢复了,日积月累关乎将来的开发效率，还好处于懵懂阶段。笔记一大堆，记忆力又不怎么好，所以web+log=blog;

SqlHelper类
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 DAL
{

/// <summary>
/// SqlHelper类 by zy 2016-3-11
/// </summary>
public class SqlHelper
{
     //如果项目中只连接了一个数据库那么可以在此定义一个固定的连接字符串

    public static string ConnectionStr { get; } =
        ConfigurationManager.ConnectionStrings["connStr"].ConnectionString;

    public static string ConnStr()
    {
        return ConfigurationManager.ConnectionStrings["connStr"].ConnectionString;
    }
    #region ExecuteNonQuery

    /// <summary>
    /// 执行sql语句返回受影响行数
    /// </summary>
    /// <param name="connectionString">连接字符串</param>
    /// <param name="cmdType">command类型</param>
    /// <param name="cmdText">sql语句</param>
    /// <param name="commandParameters">参数</param>
    /// <returns></returns>
    public static int ExecuteNonQuery(string connectionString, CommandType cmdType, string cmdText,
        params SqlParameter[] commandParameters)
    {
        SqlCommand cmd = new SqlCommand();

        using (SqlConnection conn = new SqlConnection(connectionString))
        {
            PrepareCommand(cmd, conn, null, cmdType, cmdText, commandParameters);
            int val = cmd.ExecuteNonQuery();
            cmd.Parameters.Clear();
            return val;
        }
    }

    /// <summary>
    /// 执行sql语句返回当前插入的记录id(其实是ExecuteScalar转换成id返回)
    /// </summary>
    /// <param name="connectionString">连接字符串</param>
    /// <param name="cmdType">command类型</param>
    /// <param name="cmdText">sql语句</param>
    /// <param name="returnID">返回id</param>
    /// <param name="commandParameters">参数</param>
    /// <returns></returns>
    public static int ExecuteNonQuery(string connectionString, CommandType cmdType, string cmdText,
        out int returnID, params SqlParameter[] commandParameters)
    {
        SqlCommand cmd = new SqlCommand();

        using (SqlConnection conn = new SqlConnection(connectionString))
        {
            returnID = 0;
            PrepareCommand(cmd, conn, null, cmdType, cmdText, commandParameters);
            returnID = (Int32) cmd.ExecuteScalar();
            cmd.Parameters.Clear();
            return returnID;
        }
    }

    /// <summary>
    /// 执行sql语句返回受影响行数(数据库连接SqlConnection)
    /// </summary>
    /// <param name="connection">SqlConnection连接</param>
    /// <param name="cmdType">command类型</param>
    /// <param name="cmdText">sql语句</param>
    /// <param name="commandParameters">参数</param>
    /// <returns></returns>
    public static int ExecuteNonQuery(SqlConnection connection, CommandType cmdType, string cmdText,
        params SqlParameter[] commandParameters)
    {
        SqlCommand cmd = new SqlCommand();

        PrepareCommand(cmd, connection, null, cmdType, cmdText, commandParameters);
        int val = cmd.ExecuteNonQuery();
        cmd.Parameters.Clear();
        return val;
    }

    /// <summary>
    /// 执行sql语句返回受影响行数(事务SqlTransaction)
    /// </summary>
    /// <param name="trans">SqlTransaction事务</param>
    /// <param name="cmdType">command类型</param>
    /// <param name="cmdText">sql语句</param>
    /// <param name="commandParameters">参数</param>
    /// <returns></returns>
    public static int ExecuteNonQuery(SqlTransaction trans, CommandType cmdType, string cmdText,
        params SqlParameter[] commandParameters)
    {
        SqlCommand cmd = new SqlCommand();
        PrepareCommand(cmd, trans.Connection, trans, cmdType, cmdText, commandParameters);
        int val = cmd.ExecuteNonQuery();
        cmd.Parameters.Clear();
        return val;
    }

    #endregion

    #region ExecuteScalar

    /// <summary>
    /// 执行sql语句返回结果集第一行第一列
    /// </summary>
    /// <param name="connectionString">连接字符串</param>
    /// <param name="cmdType">Command类型</param>
    /// <param name="cmdText">sql语句</param>
    /// <param name="commandParameters">参数</param>
    /// <returns></returns>
    public static object ExecuteScalar(string connectionString, CommandType cmdType, string cmdText,
        params SqlParameter[] commandParameters)
    {
        SqlCommand cmd = new SqlCommand();

        using (SqlConnection connection = new SqlConnection(connectionString))
        {
            PrepareCommand(cmd, connection, null, cmdType, cmdText, commandParameters);
            object val = cmd.ExecuteScalar();
            cmd.Parameters.Clear();
            return val;
        }
    }

    /// <summary>
    /// 执行sql语句返回结果集第一行第一列(事务)
    /// </summary>
    /// <param name="trans">SqlTransaction事务</param>
    /// <param name="cmdType">Command类型</param>
    /// <param name="cmdText">sql语句</param>
    /// <param name="commandParameters">参数</param>
    /// <returns></returns>
    public static object ExecuteScalar(SqlTransaction trans, CommandType cmdType, string cmdText,
        params SqlParameter[] commandParameters)
    {
        SqlCommand cmd = new SqlCommand();
        PrepareCommand(cmd, trans.Connection, trans, cmdType, cmdText, commandParameters);
        object val = cmd.ExecuteScalar();
        cmd.Parameters.Clear();
        return val;
    }

    /// <summary>
    /// 执行sql语句返回结果集第一行第一列(数据库连接)
    /// </summary>
    /// <param name="connection">SqlConnection连接</param>
    /// <param name="cmdType">Command类型</param>
    /// <param name="cmdText">sql语句</param>
    /// <param name="commandParameters">参数</param>
    /// <returns></returns>
    public static object ExecuteScalar(SqlConnection connection, CommandType cmdType, string cmdText,
        params SqlParameter[] commandParameters)
    {
        SqlCommand cmd = new SqlCommand();

        PrepareCommand(cmd, connection, null, cmdType, cmdText, commandParameters);
        object val = cmd.ExecuteScalar();
        cmd.Parameters.Clear();
        return val;
    }

    #endregion

    #region ExecuteReader

    /// <summary>
    /// 执行sql语句返回reader
    /// </summary>
    /// <param name="connectionString">连接字符串</param>
    /// <param name="cmdType">command类型</param>
    /// <param name="cmdText">sql语句</param>
    /// <param name="commandParameters">参数</param>
    /// <returns></returns>
    public static SqlDataReader ExecuteReader(string connectionString, CommandType cmdType, string cmdText,
        params SqlParameter[] commandParameters)
    {
        SqlCommand cmd = new SqlCommand();
        SqlConnection conn = new SqlConnection(connectionString);
        try
        {
            PrepareCommand(cmd, conn, null, cmdType, cmdText, commandParameters);
            SqlDataReader rdr = cmd.ExecuteReader(CommandBehavior.CloseConnection);
            cmd.Parameters.Clear();
            return rdr;
        }
        catch
        {
            conn.Close();
            throw;
        }
    }

    #endregion

    #region DataSet

    /// <summary>
    /// 执行sql语句返回DataSet结果集(无参数)
    /// </summary>
    /// <param name="connectionString">连接字符串</param>
    /// <param name="commandType">command类型</param>
    /// <param name="commandText">sql语句</param>
    /// <returns></returns>
    public static DataSet ExecuteDataset(string connectionString, CommandType commandType, string commandText)
    {
        return ExecuteDataset(connectionString, commandType, commandText, (SqlParameter[]) null);
    }

    /// <summary>
    /// 执行sql语句返回DataSet结果集
    /// </summary>
    /// <param name="connectionString">连接字符串</param>
    /// <param name="commandType">command类型</param>
    /// <param name="commandText">sql语句</param>
    /// <param name="commandParameters">参数</param>
    /// <returns></returns>
    public static DataSet ExecuteDataset(string connectionString, CommandType commandType, string commandText,
        params SqlParameter[] commandParameters)
    {
        //创建数据库连接完成后dispose
        using (SqlConnection cn = new SqlConnection(connectionString))
        {
            cn.Open();

            //根据数据库连接调用具体方法
            return ExecuteDataset(cn, commandType, commandText, commandParameters);
        }
    }

    /// <summary>
    /// 执行sql语句返回DataSet结果集(数据库连接SqlConnection)
    /// </summary>
    /// <param name="connection">SqlConnection连接</param>
    /// <param name="commandType">command类型</param>
    /// <param name="commandText">sql语句</param>
    /// <param name="commandParameters">参数</param>
    /// <returns></returns>
    public static DataSet ExecuteDataset(SqlConnection connection, CommandType commandType, string commandText,
        params SqlParameter[] commandParameters)
    {
        //创建command
        SqlCommand cmd = new SqlCommand();
        //准备command对象
        PrepareCommand(cmd, connection, (SqlTransaction) null, commandType, commandText, commandParameters);

        //创建SqlDataAdapter和DataSet
        SqlDataAdapter da = new SqlDataAdapter(cmd);
        DataSet ds = new DataSet();

        //把结果集装进dataset
        da.Fill(ds);

        //返回
        return ds;
    }

    #endregion DataSet

    #region DataTable

    /// <summary>
    /// 执行sql语句返回DataTable结果集(无参数)
    /// </summary>
    /// <param name="connectionString">连接字符串</param>
    /// <param name="commandType">command类型</param>
    /// <param name="commandText">sql语句</param>
    /// <returns></returns>
    public static DataTable ExecuteDataTable(string connectionString, CommandType commandType, string commandText)
    {
        return ExecuteDataTable(connectionString, commandType, commandText, (SqlParameter[])null);
    }

    /// <summary>
    /// 执行sql语句返回DataTable结果集
    /// </summary>
    /// <param name="connectionString">连接字符串</param>
    /// <param name="commandType">command类型</param>
    /// <param name="commandText">sql语句</param>
    /// <param name="commandParameters">参数</param>
    /// <returns></returns>
    public static DataTable ExecuteDataTable(string connectionString, CommandType commandType, string commandText,
        params SqlParameter[] commandParameters)
    {
        using (SqlConnection cn = new SqlConnection(connectionString))
        {
            cn.Open();
            return ExecuteDataTable(cn, commandType, commandText, commandParameters);
        }
    }

    /// <summary>
    /// 执行sql语句返回DataTable结果集
    /// </summary>
    /// <param name="connection">SqlConnection连接</param>
    /// <param name="commandType">command类型</param>
    /// <param name="commandText">sql语句</param>
    /// <param name="commandParameters">参数</param>
    /// <returns></returns>
    public static DataTable ExecuteDataTable(SqlConnection connection, CommandType commandType, string commandText,
        params SqlParameter[] commandParameters)
    {
        SqlCommand cmd = new SqlCommand();
        PrepareCommand(cmd, connection, (SqlTransaction) null, commandType, commandText, commandParameters);

        SqlDataAdapter da = new SqlDataAdapter(cmd);
        DataTable dt = new DataTable();

        da.Fill(dt);

        return dt;
    }

    #endregion DataTable

    #region PrepareCommand

    /// <summary>
    /// 准备Command对象
    /// </summary>
    /// <param name="cmd">SqlCommand 对象</param>
    /// <param name="conn">SqlConnection 对象</param>
    /// <param name="trans">SqlTransaction 对象</param>
    /// <param name="cmdType">Command 类型</param>
    /// <param name="cmdText">sql语句</param>
    /// <param name="cmdParms">参数</param>
    private static void PrepareCommand(SqlCommand cmd, SqlConnection conn, SqlTransaction trans,
        CommandType cmdType, string cmdText, SqlParameter[] cmdParms)
    {
        //打开SqlConnection连接
        if (conn.State != ConnectionState.Open)
            conn.Open();
        //给Command的Connection CommandText设置值
        cmd.Connection = conn;
        cmd.CommandText = cmdText;
        //如果是事务设置事务
        if (trans != null)
            cmd.Transaction = trans;
        //Command类型
        cmd.CommandType = cmdType;
        //Command参数
        if (cmdParms != null)
        {
            foreach (SqlParameter parm in cmdParms)
            {
                //在此可以操作参数比如把参数值里的英文逗号全部改为中文逗号或者其他操作
                switch (parm.SqlDbType)
                {
                    case SqlDbType.Char:
                    case SqlDbType.NChar:
                    case SqlDbType.NText:
                    case SqlDbType.NVarChar:
                    case SqlDbType.Text:
                    case SqlDbType.VarChar:
                        if (parm.Value != null && parm.Value != DBNull.Value && parm.ParameterName != "@SQLClause")
                        {
                            string tmp = parm.Value.ToString();
                            tmp = tmp.Replace(",", "，");
                            tmp = tmp.Replace("'", "＇");
                            parm.Value = tmp;
                        }
                        break;
                }

                 //把参数添加到Command中的Parameters中
                 cmd.Parameters.Add(parm);
             }
         }
     }

   #endregion
}

}
原文地址不得，忘记哪里CV的了。

标签：语句,string,cmd,SqlConnection,笔记,sql,ADO,Net,commandParameters
来源： https://www.cnblogs.com/fenqinearl/p/10662156.html