c# - 如何在 C# 中读写二进制文件？

Question

我正在尝试用 C# 编写一个应用程序，它将数据写入二进制文件，然后读取它。问题是，当我尝试读取它时，应用程序崩溃并出现错误“无法读取超出流末尾的内容。”

代码如下:

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using System.IO;

namespace Read_And_Write_To_Binary
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void btnSave_Click(object sender, EventArgs e)
        {
            SaveFileDialog SaveFileDialog = new SaveFileDialog();
            SaveFileDialog.Title = "Save As...";
            SaveFileDialog.Filter = "Binary File (*.bin)|*.bin";
            SaveFileDialog.InitialDirectory = @"C:\";
            if (SaveFileDialog.ShowDialog() == DialogResult.OK)
            {
                FileStream fs = new FileStream(SaveFileDialog.FileName, FileMode.Create);
                // Create the writer for data.
                BinaryWriter bw = new BinaryWriter(fs);

                string Name = Convert.ToString(txtName.Text);
                int Age = Convert.ToInt32(txtAge.Text);
                bw.Write(Name);
                bw.Write(Age);

                fs.Close();
                bw.Close();
            }
         }

        private void btnOpen_Click(object sender, EventArgs e)
        {
            OpenFileDialog OpenFileDialog = new OpenFileDialog();
            OpenFileDialog.Title = "Open File...";
            OpenFileDialog.Filter = "Binary File (*.bin)|*.bin";
            OpenFileDialog.InitialDirectory = @"C:\";
            if (OpenFileDialog.ShowDialog() == DialogResult.OK)
            {
                FileStream fs = new FileStream(OpenFileDialog.FileName, FileMode.Create);
                BinaryReader br = new BinaryReader(fs);

                lblName.Text = br.ReadString();
                lblAge.Text = br.ReadInt32();

                fs.Close();
                br.Close();
            }
        }
    }
}

Answer 1

您正在使用 FileMode.Create 来读取文件。

您应该改用 FileMode.Open。

FileStream fs = new FileStream(SaveFileDialog.FileName, FileMode.Open);

当您打开创建文件的流时，现有文件将被重写，因此您将收到此异常，因为文件中没有可用数据。