c# - 如何使用 BinaryReader 并将数据正确输入文件？

Question

我正在做家庭作业，但完全卡住了!我想要做的是使用已经定义的输入并使用 saveDataTo() 方法将其保存到文件中，然后使用 readDataFrom() 方法读取输入。

我卡在了第一部分。我不确定是否必须先初始化 Program.cs 文件中的数据？

我不知道，我被困住了。这是代码，希望能提供一些提示，帮助我完成此任务。

-- 编辑--

我可以为 saveDataTo() 和 readDataFrom() 方法添加说明:

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.

所以这给了我一个线索，我应该使用和分配要保存在文件中的属性？

-- 编辑--

更新了那里的代码。我确实对保存到文件中的内容有疑问。我没有看到价格。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。

求助。

Answer 1

你问的是在 Program.cs 还是 Book.cs 中定义值，对吗？嗯，在Program.cs中定义值就可以了，你只需要在写入数据之前确保所有的值都给定了。

因此，由于该函数采用了一个假定已预先初始化的 BinaryWriter 参数，因此这应该有效:

public void saveDataTo(BinaryWriter w)
{
     w.Write(getAuthorName());
     //etc...
}

但是，请记住，在调用保存数据之前，您确实需要在某处(任何地方)定义所有信息。