C# Builder实现POP3信箱的监视

【 tulaoshi.com - 编程语言 】

　　前言：

　　Borland的C# Builder是一个基于C#语言的编程工具，C# Builder允许开发者用Java或CORBA工具开发，C# Builder同时也具有从多种数据库中读取数据的能力，可以混合和适应不同开发标准的能力。本文向大家介绍怎样用Borland C# Builder编写一个信箱监视程序， 程序主要是通过WinSock来进行网络通信。要实现这个程序，应对POP3协议有一定的了解，下面是对POP3协议的一个粗略的介绍，读者可以参看RFC 1225更为详细地了解该协议。

　　一、POP3协议简单介绍

　　POP3服务器程序通常在TCP端口110提供服务。当客户想要使用服务时，它便与服务器建立一个TCP连接。一旦连接建立，POP3服务器就向客户发送一条欢迎消息。然后客户开始给服务器发送命令，服务器则给出相应的回答。POP3的命令由一个关键词或者关键词加参数组成。每个命令以回车换行（0xD0xA）作为结束标志。对于所有的命令，POP3服务器都会提供一个回答。服务器的回答由一个状态标志加一些附加信息组成。目前使用的两个标志是＋OK和－ERR，分别表示客户的命令是否合法。所有的回答也是以回车换行结束。与本文讨论的话题相关的四个POP3命令是USER、PASS、STAT和QUIT。

　　USER命令

　　格式USER name

　　其中name是用户在该POP3服务器上的用户标识。客户应该在接到服务器的欢迎消息后或者在上一个USER或者PASS失败之后可以发送此命令。

　　PASS命令

　　格式PASS string

　　其中string为该用户的密码。客户在发送了USER命令并且收到了＋OK的回答之后方可发送此命令。如果用户名和密码都正确，服务器回答＋OK，否则－ERR。

　　STAT命令

　　格式STAT

　　STAT命令来查看邮箱的情况。STAT命令的回应中有两个数字，分别表示邮件的数量和邮件的大小。

　　QUIT命令

　　从POP3服务器上退出登录。

　　二、POP3信箱的监视程序分析

　　我们准备的做的程序要实现以下功能：

　　1.托盘图标，程序一运行，只显示一托盘图标，右键点击托盘图标可弹出菜单。

　　2.获取邮件数量，根据POP3协议，得到邮件的数量。

　　3.读取和写注册表，注册表中保存服务器、用户名、密码等设置。

　　4.用户提示信息，这里我们做一个与MSN一样的提示窗口。

　　三、程序实现

　　下面我们就不妨着手我们的程序。首先，打开Borland C# builder，新建一个项目，菜单 File-C# Applicaion 项目的名称不妨设为"chkpop3"，图示如下：

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　　设计主窗口，如下图：

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　　主要包括五个文本框，五个标签，三个按钮，一个选择框和一个timer。

　　WinForm设置如下：

　　text:收取邮件

　　startPosition:CenterScreen

　　MaximizeBox:false

　　三个按钮:

　　最小化按钮：最小化窗口，这里就是隐藏主窗口。

　　取邮件按钮：实现取得POP3信箱中的邮件数量，并用信息窗口提示。

　　应用按钮：保存设置到注册表中

　　timer1的功能：完成在一定时间间隔内取POP3信箱中邮件数量。

　　1.托盘的实现：

　　从tool palette选择组件contextMenu(加两个菜单项，设置和退出)、notifyIcon(text设为：邮箱检测，图标ICON选择一个16x16的小图标即可，contextMenu设为前面加入的contextMenu1，Visible设为true) 这样一个完整的托盘程序就设好了。

　　2.用户提示信息的实现：

　　新建一窗口WinForm1，把窗体的FormBorderStyle属性设置为None（无边框模式），然后把TopMost属性（总在最上方）属性设置为True，把ShowInTaskbar属性(是否在 Windows 任务栏中显示窗体)设置为False，并在窗体上加上一文字标签，将窗体的背景设置为你想要的图片和合适的大小。最后再放上三个Timer控件，其中，timer1控制窗体滚出的动画，timer2控制窗体停留时间，timer3控制窗体的滚入动画，将它们的Interval属性设置为10，如图：

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　　WinForm1代码如下：

using System;using System.Drawing;using System.Collections;using System.ComponentModel;using System.Windows.Forms;using System.Data;namespace pop3{/// summary/// Summary description for WinForm1./// /summarypublic class WinForm1 : System.Windows.Forms.Form{/// summary/// Required designer variable./// /summaryprivate System.ComponentModel.IContainer components;private System.Windows.Forms.Timer timer1;private System.Windows.Forms.Timer timer2;private System.Windows.Forms.Timer timer3;private System.Windows.Forms.LinkLabel linkLabel1;public string str_num;public WinForm1(){//// Required for Windows Form Designer support//InitializeComponent();//// TODO: Add any constructor code after InitializeComponent call//}/// summary/// Clean up any resources being used./// /summaryprotected override void Dispose (bool disposing){if (disposing){if (components != null){components.Dispose();}}base.Dispose(disposing);}#region Windows Form Designer generated code/// summary/// Required method for Designer support - do not modify/// the contents of this method with the code editor./// /summaryprivate void InitializeComponent(){this.components = new System.ComponentModel.Container();System.Resources.ResourceManager resources = new System.Resources.ResourceManager(typeof(WinForm1));this.timer1 = new System.Windows.Forms.Timer(this.components);this.timer2 = new System.Windows.Forms.Timer(this.components);this.timer3 = new System.Windows.Forms.Timer(this.components);this.linkLabel1 = new System.Windows.Forms.LinkLabel();this.SuspendLayout();//// timer1//this.timer1.Interval = 10;this.timer1.Tick += new System.EventHandler(this.timer1_Tick);//// timer2//this.timer2.Interval = 10;this.timer2.Tick += new System.EventHandler(this.timer2_Tick);//// timer3//this.timer3.Interval = 10;this.timer3.Tick += new System.EventHandler(this.timer3_Tick);//// linkLabel1//this.linkLabel1.AutoSize = true;this.linkLabel1.BackColor = System.Drawing.Color.WhiteSmoke;this.linkLabel1.Location = new System.Drawing.Point(56, 56);this.linkLabel1.Name = "linkLabel1";this.linkLabel1.Size = new System.Drawing.Size(79, 17);this.linkLabel1.TabIndex = 0;this.linkLabel1.TabStop = true;this.linkLabel1.Text = "您有新邮件！";//// WinForm1//this.AutoScaleBaseSize = new System.Drawing.Size(6, 14);this.BackColor = System.Drawing.SystemColors.Info;this.BackgroundImage = ((System.Drawing.Image)(resources.GetObject("$this.BackgroundImage")));this.ClientSize = new System.Drawing.Size(194, 122);this.Controls.Add(this.linkLabel1);this.FormBorderStyle = System.Windows.Forms.FormBorderStyle.None;this.Name = "WinForm1";this.ShowInTaskbar = false;this.Text = "信息提示";this.TopMost = true;this.Load += new System.EventHandler(this.WinForm1_Load);this.Activated += new System.EventHandler(this.WinForm1_Activated);this.ResumeLayout(false);}#endregionprivate void WinForm1_Load(object sender, System.EventArgs e){Screen[] screens = Screen.AllScreens;Screen screen = screens[0];this.Location = new Point(screen.WorkingArea.Width - 200, screen.WorkingArea.Height - 30);this.timer2.Interval = 5000;}private void ScrollUp(){if(Height  122){this.Height += 3;this.Location = new Point(this.Location.X, this.Location.Y - 3);}else{this.timer1.Enabled = false;this.timer2.Enabled = true;}}private void ScrollDown(){if(Height  3){this.Height -= 3;this.Location = new Point(this.Location.X, this.Location.Y + 3);}else{this.timer3.Enabled = false;this.Close();}}private void timer1_Tick(object sender, System.EventArgs e){ScrollUp();}private void timer2_Tick(object sender, System.EventArgs e){timer2.Enabled = false;timer3.Enabled = true;}private void timer3_Tick(object sender, System.EventArgs e){ScrollDown();}public void ScrollShow(){this.Width = 194;this.Height = 0;this.Show();this.timer1.Enabled = true;}private void WinForm1_Activated(object sender, System.EventArgs e){linkLabel1.Text="您有"+str_num+"封新邮件！";}}}

　　具体的实现，可以参考一下网上的一篇文章：《用VC#编写仿MSN Messager的滚动提示窗口》，已经记不清出处了，可以通过这个网址http://yousoft.hi.com.cn/article_view.asp？id=6595浏览。

　　3.获取邮件数量的实现，代码见下：

string str_server;if ((tB_server.Text!="") && (tB_user.Text!="") && (tB_pwd.Text!="")){TcpClient tcpc = new TcpClient(tB_server.Text,110);Byte[] outbytes;string input;NetworkStream ns = null;try{ns = tcpc.GetStream();StreamReader sr = new StreamReader(ns);tB_status.Text=sr.ReadLine();input = "USER " + tB_user.Text + "rn";outbytes = System.Text.Encoding.ASCII.GetBytes(input.ToCharArray());ns.Write(outbytes,0,outbytes.Length)tB_status.Text=tB_status.Text+"rn"+sr.ReadLine();input = "PASS " + tB_pwd.Text + "rn";outbytes = System.Text.Encoding.ASCII.GetBytes(input.ToCharArray());ns.Write(outbytes,0,outbytes.Length)tB_status.Text=tB_status.Text+"rn"+sr.ReadLine();input = "STAT" + "rn";outbytes = System.Text.Encoding.ASCII.GetBytes(input.ToCharArray());ns.Write(outbytes,0,outbytes.Length)str_server=sr.ReadLine();str_num="";if (str_server.StartsWith("+OK")){str_num=str_server.Split(' ')[1];} else str_num="";tB_status.Text=tB_status.Text+"rn"+"A:"+str_server;input = "QUIT" + "rn";outbytes = System.Text.Encoding.ASCII.GetBytes(input.ToCharArray());ns.Write(outbytes,0,outbytes.Length)tB_status.Text=tB_status.Text+"rn"+"B:"+sr.ReadLine();}catch(InvalidOperationException ioe){tB_status.Text="Could not connect to mail server";}if (str_num!="") {WinForm1 form = new WinForm1();form.str_num=str_num;form.ScrollShow();}

　　程序与邮件服务器建立一个TCP连接，然后发送POP3的一些命令，取到服务器传回的信息，得到邮件的数量。

　　STAT命令的回应中有两个数字，分别表示邮件的数量和邮件的大小。一般格式是这样的+OK 数量 大小，所以只要根据服务器返回的信息，提取+OK，然后再按空格分隔得到数量。代码见上。

　　4.注册表的读写：

　　我们知道，要实现程序在开机后自己运行，可以通过写注册表HKEY_CURRENT_USERSoftwareMicrosoftWindowsCurrentVersionRun实现。

　　另外，为了方便用户，我们把邮件服务器，用户,密码等信息存入注册表，不用每次都再输一次。

　　保存信息代码如下：

RegistryKey rk;Registry.CurrentUser.CreateSubKey("Softwareyousoft");rk=Registry.CurrentUser.OpenSubKey("Softwareyousoft",true);rk.Setvalue("server",tB_server.Text);rk.Setvalue("user",tB_user.Text);rk.Setvalue("pwd",tB_pwd.Text);rk.Setvalue("interval",tB_mins.Text);if (cB_autorun.Checked) {rk=Registry.CurrentUser.OpenSubKey("SoftwareMicrosoftWindowsCurrentVersionRun",true);rk.Setvalue("chkmail",Application.ExecutablePath);} else{rk=Registry.CurrentUser.OpenSubKey("SoftwareMicrosoftWindowsCurrentVersionRun",true);rk.Deletevalue("chkmail");}rk.Close();

　　启动程序时读入信息：

private void WinForm_Load(object sender, System.EventArgs e){RegistryKey rk;rk=Registry.CurrentUser.OpenSubKey("Softwareyousoft",false);object srv=rk.Getvalue("server");if (srv!=null) tB_server.Text=srv.ToString();object usr=rk.Getvalue("user");if (usr!=null) tB_user.Text=usr.ToString();object pwd=rk.Getvalue("pwd");if (pwd!=null) tB_pwd.Text=pwd.ToString();object mins=rk.Getvalue("interval");if (mins!=null) tB_mins.Text=mins.ToString();rk.Close();}WinForm的完整代码如下：using System;using System.Drawing;using System.Collections;using System.ComponentModel;using System.Windows.Forms;using System.Data;using System.Net.Sockets;using System.IO;using System.Net;using Microsoft.Win32;namespace pop3{/// summary/// Summary description for WinForm./// /summarypublic class WinForm : System.Windows.Forms.Form{/// summary/// Required designer variable./// /summaryprivate System.ComponentModel.IContainer components;private System.Windows.Forms.Button button1;private System.Windows.Forms.Label label1;private System.Windows.Forms.Label label2;private System.Windows.Forms.Label label3;private System.Windows.Forms.TextBox tB_server;private System.Windows.Forms.TextBox tB_user;private System.Windows.Forms.TextBox tB_pwd;private System.Windows.Forms.TextBox tB_status;private System.Windows.Forms.NotifyIcon notifyIcon1;private System.Windows.Forms.ContextMenu contextMenu1;private System.Windows.Forms.MenuItem menuItem1;private System.Windows.Forms.MenuItem menuItem2;private System.Windows.Forms.MenuItem menuItem3;private bool f_open=true;private string str_num="";private System.Windows.Forms.Button button2;private System.Windows.Forms.Timer timer1;private System.Windows.Forms.TextBox tB_mins;private System.Windows.Forms.Label label4;private System.Windows.Forms.Label label5;private System.Windows.Forms.Button button3;private System.Windows.Forms.CheckBox cB_autorun;public WinForm(){//// Required for Windows Form Designer support//InitializeComponent();//// TODO: Add any constructor code after InitializeComponent call//}/// summary/// Clean up any resources being used./// /summaryprotected override void Dispose (bool disposing){if (disposing){if (components != null){components.Dispose();}}base.Dispose(disposing);}#region Windows Form Designer generated code/// summary/// Required method for Designer support - do not modify/// the contents of this method with the code editor./// /summaryprivate void InitializeComponent(){this.components = new System.ComponentModel.Container();System.Resources.ResourceManager resources = new System.Resources.ResourceManager(typeof(WinForm));this.button1 = new System.Windows.Forms.Button();this.label1 = new System.Windows.Forms.Label();this.label2 = new System.Windows.Forms.Label();this.label3 = new System.Windows.Forms.Label();this.tB_server = new System.Windows.Forms.TextBox();this.tB_user = new System.Windows.Forms.TextBox();this.tB_pwd = new System.Windows.Forms.TextBox();this.tB_status = new System.Windows.Forms.TextBox();this.notifyIcon1 = new System.Windows.Forms.NotifyIcon(this.components);this.contextMenu1 = new System.Windows.Forms.ContextMenu();this.menuItem1 = new System.Windows.Forms.MenuItem();this.menuItem2 = new System.Windows.Forms.MenuItem();this.menuItem3 = new System.Windows.Forms.MenuItem();this.button2 = new System.Windows.Forms.Button();this.timer1 = new System.Windows.Forms.Timer(this.components);this.tB_mins = new System.Windows.Forms.TextBox();this.label4 = new System.Windows.Forms.Label();this.label5 = new System.Windows.Forms.Label();this.button3 = new System.Windows.Forms.Button();this.cB_autorun = new System.Windows.Forms.CheckBox();this.SuspendLayout();//// button1//this.button1.Location = new System.Drawing.Point(152, 176);this.button1.Name = "button1";this.button1.TabIndex = 0;this.button1.Text = "取邮件";this.button1.Click += new System.EventHandler(this.button1_Click);//// label1//this.label1.Location = new System.Drawing.Point(24, 32);this.label1.Name = "label1";this.label1.Size = new System.Drawing.Size(80, 23);this.label1.TabIndex = 1;this.label1.Text = "邮件服务器：";//// label2//this.label2.Location = new System.Drawing.Point(48, 64);this.label2.Name = "label2";this.label2.Size = new System.Drawing.Size(56, 23);this.label2.TabIndex = 2;this.label2.Text = "用户名：";//// label3//this.label3.Location = new System.Drawing.Point(58, 96);this.label3.Name = "label3";this.label3.Size = new System.Drawing.Size(48, 23);this.label3.TabIndex = 3;this.label3.Text = "密码：";//// tB_server//this.tB_server.Location = new System.Drawing.Point(112, 24);this.tB_server.Name = "tB_server";this.tB_server.Size = new System.Drawing.Size(176, 21);this.tB_server.TabIndex = 4;this.tB_server.Text = "";this.tB_server.TextChanged += new System.EventHandler(this.tB_pwd_TextChanged);//// tB_user//this.tB_user.Location = new System.Drawing.Point(112, 60);this.tB_user.Name = "tB_user";this.tB_user.Size = new System.Drawing.Size(176, 21);this.tB_user.TabIndex = 5;this.tB_user.Text = "";this.tB_user.TextChanged += new System.EventHandler(this.tB_pwd_TextChanged);//// tB_pwd//this.tB_pwd.Location = new System.Drawing.Point(112, 91);this.tB_pwd.Name = "tB_pwd";this.tB_pwd.PasswordChar = '*';this.tB_pwd.Size = new System.Drawing.Size(176, 21);this.tB_pwd.TabIndex = 6;this.tB_pwd.Text = "";this.tB_pwd.TextChanged += new System.EventHandler(this.tB_pwd_TextChanged);//// tB_status//this.tB_status.Location = new System.Drawing.Point(16, 208);this.tB_status.Multiline = true;this.tB_status.Name = "tB_status";this.tB_status.Size = new System.Drawing.Size(328, 80);this.tB_status.TabIndex = 7;this.tB_status.Text = "";//// notifyIcon1//this.notifyIcon1.ContextMenu = this.contextMenu1;this.notifyIcon1.Icon = ((System.Drawing.Icon)(resources.GetObject("notifyIcon1.Icon")));this.notifyIcon1.Text = "邮件检测";this.notifyIcon1.Visible = true;//// contextMenu1//this.contextMenu1.MenuItems.AddRange(new System.Windows.Forms.MenuItem[] {this.menuItem1,this.menuItem2,this.menuItem3});//// menuItem1//this.menuItem1.Index = 0;this.menuItem1.Text = "设置&S";this.menuItem1.Click += new System.EventHandler(this.menuItem1_Click);//// menuItem2//this.menuItem2.Index = 1;this.menuItem2.Text = "-";//// menuItem3//this.menuItem3.Index = 2;this.menuItem3.Text = "退出&Q";this.menuItem3.Click += new System.EventHandler(this.menuItem3_Click);//// button2//this.button2.Location = new System.Drawing.Point(48, 176);this.button2.Name = "button2";this.button2.TabIndex = 8;this.button2.Text = "最小化";this.button2.Click += new System.EventHandler(this.button2_Click);//// timer1//this.timer1.Interval = 5000;this.timer1.Tick += new System.EventHandler(this.timer1_Tick);//// tB_mins//this.tB_mins.Location = new System.Drawing.Point(112, 124);this.tB_mins.Name = "tB_mins";this.tB_mins.Size = new System.Drawing.Size(144, 21);this.tB_mins.TabIndex = 10;this.tB_mins.Text = "20000";this.tB_mins.TextChanged += new System.EventHandler(this.tB_pwd_TextChanged);//// label4//this.label4.Location = new System.Drawing.Point(32, 128);this.label4.Name = "label4";this.label4.Size = new System.Drawing.Size(72, 23);this.label4.TabIndex = 9;this.label4.Text = "时间间隔：";//// label5//this.label5.Location = new System.Drawing.Point(264, 129);this.label5.Name = "label5";this.label5.Size = new System.Drawing.Size(40, 16);this.label5.TabIndex = 11;this.label5.Text = "毫秒";//// button3//this.button3.Location = new System.Drawing.Point(264, 176);this.button3.Name = "button3";this.button3.TabIndex = 12;this.button3.Text = "应用";this.button3.Click += new System.EventHandler(this.button3_Click);//// cB_autorun//this.cB_autorun.Location = new System.Drawing.Point(112, 152);this.cB_autorun.Name = "cB_autorun";this.cB_autorun.Size = new System.Drawing.Size(160, 24);this.cB_autorun.TabIndex = 13;this.cB_autorun.Text = "启动时自动执行";//// WinForm//this.AutoScaleBaseSize = new System.Drawing.Size(6, 14);this.ClientSize = new System.Drawing.Size(368, 301);this.Controls.Add(this.cB_autorun);this.Controls.Add(this.button3);this.Controls.Add(this.label5);this.Controls.Add(this.tB_mins);this.Controls.Add(this.label4);this.Controls.Add(this.button2);this.Controls.Add(this.tB_status);this.Controls.Add(this.tB_pwd);this.Controls.Add(this.tB_user);this.Controls.Add(this.tB_server);this.Controls.Add(this.label3);this.Controls.Add(this.label2);this.Controls.Add(this.label1);this.Controls.Add(this.button1);this.Icon = ((System.Drawing.Icon)(resources.GetObject("$this.Icon")));this.MaximizeBox = false;this.Name = "WinForm";this.StartPosition = System.Windows.Forms.FormStartPosition.CenterScreen;this.Text = "收取邮件";this.Load += new System.EventHandler(this.WinForm_Load);this.Activated += new System.EventHandler(this.WinForm_Activated);this.ResumeLayout(false);}#endregion/// summary/// The main entry point for the application./// /summary[STAThread]static void Main(){Application.Run(new WinForm());}private void button1_Click(object sender, System.EventArgs e){string str_server;if ((tB_server.Text!="") && (tB_user.Text!="") && (tB_pwd.Text!="")){TcpClient tcpc = new TcpClient(tB_server.Text,110);Byte[] outbytes;string input;NetworkStream ns = null;try{ns = tcpc.GetStream();StreamReader sr = new StreamReader(ns);tB_status.Text=sr.ReadLine();input = "USER " + tB_user.Text + "rn";outbytes = System.Text.Encoding.ASCII.GetBytes(input.ToCharArray());ns.Write(outbytes,0,outbytes.Length)tB_status.Text=tB_status.Text+"rn"+sr.ReadLine();input = "PASS " + tB_pwd.Text + "rn";outbytes = System.Text.Encoding.ASCII.GetBytes(input.ToCharArray());ns.Write(outbytes,0,outbytes.Length)tB_status.Text=tB_status.Text+"rn"+sr.ReadLine();input = "STAT" + "rn";outbytes = System.Text.Encoding.ASCII.GetBytes(input.ToCharArray());ns.Write(outbytes,0,outbytes.Length)str_server=sr.ReadLine();str_num="";if (str_server.StartsWith("+OK")){str_num=str_server.Split(' ')[1];} else str_num="";tB_status.Text=tB_status.Text+"rn"+str_server;input = "QUIT" + "rn";outbytes = System.Text.Encoding.ASCII.GetBytes(input.ToCharArray());ns.Write(outbytes,0,outbytes.Length)tB_status.Text=tB_status.Text+"rn"+sr.ReadLine();}catch(InvalidOperationException ioe){tB_status.Text="Could not connect to mail server";}if (str_num!="") {WinForm1 form = new WinForm1();form.str_num=str_num;form.ScrollShow();}}}private void WinForm_Activated(object sender, System.EventArgs e){if (f_open) {this.Hide();f_open=false;}}private void menuItem3_Click(object sender, System.EventArgs e){this.Close();}private void menuItem1_Click(object sender, System.EventArgs e){this.Show();this.Focus();}private void button2_Click(object sender, System.EventArgs e){this.Hide();}private void timer1_Tick(object sender, System.EventArgs e){button1_Click(sender,e);}private void tB_pwd_TextChanged(object sender, System.EventArgs e){timer1.Enabled=false;if ((tB_server.Text!="") && (tB_user.Text!="") && (tB_pwd.Text!="")){timer1.Interval=System.Convert.ToInt32(tB_mins.Text);timer1.Enabled=true;} else{timer1.Enabled=false;}}private void button3_Click(object sender, System.EventArgs e){RegistryKey rk;Registry.CurrentUser.CreateSubKey("Softwareyousoft");rk=Registry.CurrentUser.OpenSubKey("Softwareyousoft",true);rk.Setvalue("server",tB_server.Text);rk.Setvalue("user",tB_user.Text);rk.Setvalue("pwd",tB_pwd.Text);rk.Setvalue("interval",tB_mins.Text);if (cB_autorun.Checked) {rk=Registry.CurrentUser.OpenSubKey("SoftwareMicrosoftWindowsCurrentVersionRun",true);rk.Setvalue("chkmail",Application.ExecutablePath);} else{rk=Registry.CurrentUser.OpenSubKey("SoftwareMicrosoftWindowsCurrentVersionRun",true);rk.Deletevalue("chkmail");}rk.Close();}private void WinForm_Load(object sender, System.EventArgs e){RegistryKey rk;rk=Registry.CurrentUser.OpenSubKey("Softwareyousoft",false);object srv=rk.Getvalue("server");if (srv!=null) tB_server.Text=srv.ToString();object usr=rk.Getvalue("user");if (usr!=null) tB_user.Text=usr.ToString();object pwd=rk.Getvalue("pwd");if (pwd!=null) tB_pwd.Text=pwd.ToString();object mins=rk.Getvalue("interval");if (mins!=null) tB_mins.Text=mins.ToString();rk.Close();}}}

　　按F9编译程序并运行。如图：

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　　四．小结：

　　本文向读者介绍了如何运用Borland C# builder实现POP3信箱的监视，其中大量运用了Windows Forms编程和.Net框架下的网络编程的原理。通过本文，希望能使读者对.Net中的Borland C# builder有一个感性的认识，同时对Windows Forms编程和其中的网络编程也有个大致的了解。如果有兴趣，可以到悠游在线(网址：http://yousoft.hi.com.cn)下载全部的源代码或与本人交流。