CodeGo.net>如何使用BinaryReader和正确地输入数据到文件？

我正在做作业,我完全陷入困境！我正在尝试使用已定义的输入,并通过使用saveDataTo()方法将其保存到文件中,并通过使用readDataFrom()方法来读取输入.

我停留在第一部分.我不确定是否必须先初始化Program.cs文件中的数据？

我不知道,我被卡住了.这是代码,并希望获得一些技巧来实现这一目标.

-编辑-

我可以同时为saveDataTo()和readDataFrom()方法添加指令：

The saveDataTo( ) method takes a parameter of BinaryWriter. The method
writes the values of all 5 properties of an book object to a file
stream associated with the writer (the association is done in the
Main( ) method of Program class). There is no need to open and close
the file stream and binary writer inside this method.

The readDataFrom( ) method takes a parameter of BinaryReader. The
method reads the values of all five properties of the Book object from
a file stream associated with the reader (the association is done in
the Main( ) method of Program class). There is no need to open and
close the file stream and binary reader inside this method.

这样就给了我一个线索,我应该使用它并分配要保存在文件中的属性？

-编辑-

在此更新了代码.我确实对保存到文件中的内容有疑问.没有显示价格.这是为什么？

ff.APublisherNameTitle  FirstNameLastName

Program.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO;

namespace Lab_7
{
    class Program
    {
        private const string FILE_NAME = "lab07.dat";

        static void Main(string[] args)
        {
            //char ask;

            /*
            do
            {
                Console.Write("Enter Book Title: ");
                publication.Title = Console.ReadLine();
                Console.Write("Enter Author's First Name: ");
                book.AuthorFirstName = Console.ReadLine();
                Console.Write("Enter Author's Last Name: ");
                book.AuthorLastName = Console.ReadLine();
                Console.Write("Enter Publisher's Name: ");
                publication.PublisherName = Console.ReadLine();
                Console.Write("Enter Book Price: $");
                publication.Price = float.Parse(Console.ReadLine());
                Console.Write("Would like to enter another book? [Y or N] ");
                ask = char.Parse(Console.ReadLine().ToUpper());
            }
            while (ask == char.Parse("Y"));
            */

            Book book = new Book();

            book.Price = 10.9F;
            book.Title = "Title";
            book.PublisherName = "PublisherName";
            book.AuthorFirstName = "FirstName";
            book.AuthorLastName = "LastName";

            FileStream fileStream = new FileStream(FILE_NAME, FileMode.OpenOrCreate);
            BinaryWriter write = new BinaryWriter(fileStream);
            book.saveDataTo(write);
            write.Close();

            fileStream = new FileStream(FILE_NAME, FileMode.Open, FileAccess.Read);
            BinaryReader read = new BinaryReader(fileStream);
            book.readDataFrom(read);
            read.Close();
        }
    }
}

Publication.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO;

namespace Lab_7
{
    class Publication
    {
        private float price;
        private string publisherName, title;

        public float Price
        {
            get
            {
                return price;
            }
            set
            {
                price = value;
            }
        }

        public string PublisherName
        {
            get
            {
                return publisherName;
            }
            set
            {
                publisherName = value;
            }
        }

        public string Title
        {
            get
            {
                return title;
            }
            set
            {
                title = value;
            }
        }

        public void display()
        {
            Console.WriteLine("{0}\n{1}\n{2}", title, publisherName, price);
        }
    }
}

Book.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO;

namespace Lab_7
{
    class Book : Publication
    {
        private string authorFirstName, authorLastName;

        public string AuthorFirstName
        {
            get
            {
                return authorFirstName;
            }
            set
            {
                authorFirstName = value;
            }
        }

        public string AuthorLastName
        {
            get
            {
                return authorLastName;
            }
            set
            {
                authorLastName = value;
            }
        }

        public new void display()
        {
        }

        public string getAuthorName()
        {
            return authorFirstName + " " + authorLastName;
        }

        public void readDataFrom(BinaryReader r)
        {
            Price = r.ReadInt32();
            PublisherName = r.ReadString();
            Title = r.ReadString();
            authorFirstName = r.ReadString();
            authorLastName = r.ReadString();
        }

        public void saveDataTo(BinaryWriter w)
        {
            w.Write(base.Price);
            w.Write(base.PublisherName);
            w.Write(base.Title);
            w.Write(AuthorFirstName);
            w.Write(AuthorLastName);
        }
    }
}

问候.

HelpNeeder.

解决方法:

您将参数分配给2个不同的对象,请参见：

Publication publication = new Publication(); 
Book book = new Book(); 

两者都是驻留在内存中的单个实例.

您要么必须像下面那样参考出版物到书：

Book book = new Book(); 
Publication publication = (Publication)book;

或仅将当前分配给出版物的值直接分配给该书,这样：

publication.PublisherName = "PublisherName"; 

变成

book.PublisherName = "PublisherName"; 

除此之外,您使用的是C#,而不是Java.按照惯例,以大写字母(Pascal Case)开始您的方法是正常的

编辑

您现在在重新获取价格时显示了价格,因为您将其写为一个浮动字段(或加倍,看不到定义)并将其读为整数.

从r.ReadInt32()更改；到r.ReadDouble();或r.ReadSingle()

标签：binaryreader,binarywriter,c,methods
来源： https://codeday.me/bug/20191202/2086633.html