只允许程序运行一次的代码

using System;

using System.Collections.Generic;

using System.Linq;

using System.Windows.Forms;

using System.Threading;

namespace RunOnce

{

static class Program

{

/// <summary>

/// 应用程序的主入口点。

/// </summary>

[STAThread]

static void Main()

{

bool createNew = false;

using (new Semaphore(0, 1, "MyAppIdentify", out createNew))

{

if (createNew)

{

Application.EnableVisualStyles();

Application.SetCompatibleTextRenderingDefault(false);

Application.Run(new Form1());

}

else

{

MessageBox.Show("已经有程序在运行!");

}

}

}

}

}