C# 中无法在流的结尾之外进行读取处理BinaryReader（）

再窗口体中放置1各编辑框控件，用来输入小于255得数，放置2个按钮控件，标题分别“输入下一个”和“存入输入得数”。单击标题为“输入下一个数按钮”记录输入得数，清空编辑控件，准被输入下一个数 。单击标题存“入输入得数”的按钮，存入文件中。再加一个按钮“读文件”的按钮，读入文件内容，在listbox控件显示。

//自动代码
namespace l_6_1
{
    partial class Form1
    {
        /// <summary>
        /// 必需的设计器变量。
        /// </summary>
        private System.ComponentModel.IContainer components = null;

        /// <summary>
        /// 清理所有正在使用的资源。
        /// </summary>
        /// <param name="disposing">如果应释放托管资源，为 true；否则为 false。</param>
        protected override void Dispose(bool disposing)
        {
            if (disposing && (components != null))
            {
                components.Dispose();
            }
            base.Dispose(disposing);
        }

        #region Windows 窗体设计器生成的代码

        /// <summary>
        /// 设计器支持所需的方法 - 不要
        /// 使用代码编辑器修改此方法的内容。
        /// </summary>
        private void InitializeComponent()
        {
            this.textBox1 = new System.Windows.Forms.TextBox();
            this.butnext = new System.Windows.Forms.Button();
            this.butsave = new System.Windows.Forms.Button();
            this.button3 = new System.Windows.Forms.Button();
            this.listBox1 = new System.Windows.Forms.ListBox();
            this.label1 = new System.Windows.Forms.Label();
            this.SuspendLayout();
            // 
            // textBox1
            // 
            this.textBox1.Location = new System.Drawing.Point(137, 6);
            this.textBox1.Name = "textBox1";
            this.textBox1.Size = new System.Drawing.Size(100, 21);
            this.textBox1.TabIndex = 0;
            this.textBox1.TextChanged += new System.EventHandler(this.textBox1_TextChanged);
            // 
            // butnext
            // 
            this.butnext.Location = new System.Drawing.Point(14, 33);
            this.butnext.Name = "butnext";
            this.butnext.Size = new System.Drawing.Size(76, 21);
            this.butnext.TabIndex = 1;
            this.butnext.Text = "输入下一个";
            this.butnext.UseVisualStyleBackColor = true;
            this.butnext.Click += new System.EventHandler(this.button1_Click);
            // 
            // butsave
            // 
            this.butsave.Location = new System.Drawing.Point(111, 32);
            this.butsave.Name = "butsave";
            this.butsave.Size = new System.Drawing.Size(76, 23);
            this.butsave.TabIndex = 2;
            this.butsave.Text = "存输入得数";
            this.butsave.UseVisualStyleBackColor = true;
            this.butsave.Click += new System.EventHandler(this.butsave_Click);
            // 
            // button3
            // 
            this.button3.Location = new System.Drawing.Point(193, 33);
            this.button3.Name = "button3";
            this.button3.Size = new System.Drawing.Size(75, 23);
            this.button3.TabIndex = 3;
            this.button3.Text = "读文件";
            this.button3.UseVisualStyleBackColor = true;
            this.button3.Click += new System.EventHandler(this.button3_Click);
            // 
            // listBox1
            // 
            this.listBox1.FormattingEnabled = true;
            this.listBox1.ItemHeight = 12;
            this.listBox1.Items.AddRange(new object[] {
            ""});
            this.listBox1.Location = new System.Drawing.Point(-2, 64);
            this.listBox1.Name = "listBox1";
            this.listBox1.Size = new System.Drawing.Size(296, 208);
            this.listBox1.TabIndex = 4;
            this.listBox1.SelectedIndexChanged += new System.EventHandler(this.listBox1_SelectedIndexChanged);
            // 
            // label1
            // 
            this.label1.AutoSize = true;
            this.label1.Location = new System.Drawing.Point(12, 9);
            this.label1.Name = "label1";
            this.label1.Size = new System.Drawing.Size(107, 12);
            this.label1.TabIndex = 5;
            this.label1.Text = "输入小于255的数：";
            // 
            // Form1
            // 
            this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 12F);
            this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
            this.ClientSize = new System.Drawing.Size(292, 266);
            this.Controls.Add(this.label1);
            this.Controls.Add(this.listBox1);
            this.Controls.Add(this.button3);
            this.Controls.Add(this.butsave);
            this.Controls.Add(this.butnext);
            this.Controls.Add(this.textBox1);
            this.Name = "Form1";
            this.Text = "Form1";
            this.ResumeLayout(false);
            this.PerformLayout();

        }

        #endregion

        private System.Windows.Forms.TextBox textBox1;
        private System.Windows.Forms.Button butnext;
        private System.Windows.Forms.Button butsave;
        private System.Windows.Forms.Button button3;
        private System.Windows.Forms.ListBox listBox1;
        private System.Windows.Forms.Label label1;
    }
}


//手工添加代码

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

namespace l_6_1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void textBox1_TextChanged(object sender, EventArgs e)
        {

        }

        private void button1_Click(object sender, EventArgs e)
        {

                int a = Convert.ToInt32(textBox1.Text);
                FileStream fs = new FileStream(@"D:ga.txt", FileMode.Append);
                BinaryWriter w = new BinaryWriter(fs);
                w.Write(a);
                textBox1.Clear();
                w.Close();
          
        }
        private void button3_Click(object sender, EventArgs e)
        {
          
                FileInfo fileInfo = new FileInfo(@"D:ga.txt");
                string[] a = new string[fileInfo.Length];
                FileStream fs = new FileStream(@"D:ga.txt", FileMode.Open);
                BinaryReader r = new BinaryReader(fs);
                for (int i = 0; i < fileInfo.Length; i+=4)
                {

                    a[i] = Convert.ToString(r.ReadInt32());
                    listBox1.Items.Add(a[i]);

                }
                r.Close();
           

        }



        private void butsave_Click(object sender, EventArgs e)
        {
            int a = Convert.ToInt32(textBox1.Text);
            FileStream fs = new FileStream(@"D:ga.txt", FileMode.Append);
            BinaryWriter w = new BinaryWriter(fs);
            w.Write(a);
            w.Close();
        }

        private void listBox1_SelectedIndexChanged(object sender, EventArgs e)
        {

        }

 


      
    }
}