一、通过系统事件
1、实现如下：
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Threading;
using System.Runtime.InteropServices; namespace Example
{
public class SinglonProgram
{ #region 字段 //显示的主窗体
private Form mainForm; //线程同步事件
private static EventWaitHandle programWaitHandle; #endregion #region 属性 #endregion #region 构造函数 public SinglonProgram(Form showForm)
{
this.mainForm = showForm; //注册一个等待WaitHandle的委托
ThreadPool.RegisterWaitForSingleObject(programWaitHandle, (obj, timeOut) =>
{
ShowForm();
},
null, -, false); } #endregion #region 私有函数 显示窗体、等 /// <summary>
/// 显示窗体
/// </summary>
private void ShowForm()
{
//在拥有mainForm窗体的线程上执行无参委托（Action）
this.mainForm.Invoke(new Action(() =>
{
this.mainForm.Visible = true;
if(this.mainForm.WindowState == FormWindowState.Minimized)
{
this.mainForm.WindowState = FormWindowState.Normal;
}
this.mainForm.Show(); bool isForeground = SetForegroundWindow(this.mainForm.Handle);
MessageBox.Show(isForeground.ToString());
}
));
} #endregion #region 公共函数 只有一个程序运行 /// <summary>
/// 是否创建了已命名的系统事件
/// </summary>
/// <returns></returns>
public static bool isNamedSystemEvent()
{
bool createdNew;
programWaitHandle = new EventWaitHandle(true, EventResetMode.AutoReset, Application.ProductName, out createdNew);
return !createdNew;
} /// <summary>
/// 确保只有一个程序运行
/// </summary>
public static void Confirm()
{
// 如果该命名事件已命名(运行实例已经存在)，则发事件通知并退出
if (isNamedSystemEvent())
{
programWaitHandle.Set(); //将事件状态设置为终止状态，允许一个或多个等待线程继续
Environment.Exit();
}
} #endregion #region 接口函数 激活窗体且前端显示等 /// <summary>
/// 前端显示且激活窗体
/// </summary>
/// <param name="hWnd">窗体句柄</param>
/// <returns></returns>
[DllImport("user32.dll")]
public static extern bool SetForegroundWindow(IntPtr hWnd); #endregion #region 虚函数 #endregion
}
}
2、调用如下：
static class Program
{
/// <summary>
/// 应用程序的主入口点。
/// </summary>
[STAThread]
static void Main()
{
SinglonProgram.Confirm();
Application.EnableVisualStyles();
Application.SetCompatibleTextRenderingDefault(false);
Application.Run(new frmMain());
}
}
二、通过查询线程
具体如下：（测试时发现，不调试和调试区别下会产生两个程序）
using System;
using System.Collections.Generic;
using System.Linq;
using System.Windows.Forms;
using System.Runtime.InteropServices;
using System.Diagnostics;
using System.Reflection; namespace Test
{
static class Program
{
/// <summary>
/// 该函数设置由不同线程产生的窗口的显示状态。
/// </summary>
/// <param name="hWnd">窗口句柄</param>
/// <param name="cmdShow">指定窗口如何显示。查看允许值列表，请查阅ShowWlndow函数的说明部分。</param>
/// <returns>如果函数原来可见，返回值为非零；如果函数原来被隐藏，返回值为零。</returns>
[DllImport("User32.dll")]
private static extern bool ShowWindowAsync(IntPtr hWnd, int cmdShow);
/// <summary>
/// 该函数将创建指定窗口的线程设置到前台，并且激活该窗口。键盘输入转向该窗口，并为用户改各种可视的记号。系统给创建前台窗口的线程分配的权限稍高于其他线程。
/// </summary>
/// <param name="hWnd">将被激活并被调入前台的窗口句柄。</param>
/// <returns>如果窗口设入了前台，返回值为非零；如果窗口未被设入前台，返回值为零。</returns>
[DllImport("User32.dll")]
private static extern bool SetForegroundWindow(IntPtr hWnd);
private const int WS_SHOWNORMAL = ; /// <summary>
/// 应用程序的主入口点。
/// </summary>
[STAThread]
static void Main()
{
Application.EnableVisualStyles();
Application.SetCompatibleTextRenderingDefault(false);
Process instance = RunningInstance();
if (instance == null)
{
Form1 frm = new Form1();
Application.Run(new Form1());
}
else
{
HandleRunningInstance(instance);
} } /// <summary>
/// 获取正在运行的实例，没有运行的实例返回null;
/// </summary>
public static Process RunningInstance()
{
Process current = Process.GetCurrentProcess();
Process[] processes = Process.GetProcessesByName(current.ProcessName);
foreach (Process process in processes)
{
if (process.Id != current.Id)
{
if (Assembly.GetExecutingAssembly().Location.Replace("/", "\\") == current.MainModule.FileName)
{
return process;
}
}
}
return null;
} /// <summary>
/// 显示已运行的程序。
/// </summary>
public static void HandleRunningInstance(Process instance)
{
ShowWindowAsync(instance.MainWindowHandle, WS_SHOWNORMAL); //显示，可以注释掉
SetForegroundWindow(instance.MainWindowHandle); //放到前端
} }
}
三、互斥体
/// <summary>
/// 应用程序的主入口点。
/// </summary>
[STAThread]
static void Main()
{
Application.EnableVisualStyles();
Application.SetCompatibleTextRenderingDefault(false);
Process instance = RunningInstance(); bool blnIsRunning;
Mutex mutexApp = new Mutex(false, Assembly.GetExecutingAssembly().FullName, out blnIsRunning);
if (!blnIsRunning)
{
MessageBox.Show("程序已经运行！", "提示", MessageBoxButtons.OK, MessageBoxIcon.Exclamation);
return;
} Application.Run(new Form1()); }
四、额外
public void A()
{
//=====创建互斥体法：=====
bool blnIsRunning;
Mutex mutexApp = new Mutex(false, Assembly.GetExecutingAssembly().FullName, out blnIsRunning);
if (!blnIsRunning)
{
MessageBox.Show("程序已经运行！", "提示",MessageBoxButtons.OK, MessageBoxIcon.Exclamation);
return;
}
} public void B()
{
//保证同时只有一个客户端在运行
System.Threading.Mutex mutexMyapplication = new System.Threading.Mutex(false, "OnePorcess.exe");
if (!mutexMyapplication.WaitOne(, false))
{
MessageBox.Show("程序" + Application.ProductName + "已经运行！", Application.ProductName,
MessageBoxButtons.OK, MessageBoxIcon.Error);
return;
}
} public void c()
{
//=====判断进程法：(修改程序名字后依然能执行)=====
Process current = Process.GetCurrentProcess();
Process[] processes = Process.GetProcessesByName(current.ProcessName);
foreach (Process process in processes)
{
if (process.Id != current.Id)
{
if (process.MainModule.FileName == current.MainModule.FileName)
{
MessageBox.Show("程序已经运行！", Application.ProductName,
MessageBoxButtons.OK, MessageBoxIcon.Exclamation);
return;
}
}
}
}