c#只允许运行一个程序(转载)

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using System;
using System.Drawing;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;
using System.Data;
using System.Threading;
using System.Runtime.InteropServices;
using System.Reflection;
using System.Diagnostics;

namespace Jackch
{
static class Program
{
/// <summary>
/// 应用程序的主入口点。
/// </summary>
///

//只允许运行一个程序
[DllImport("User32.dll")]
private static extern bool ShowWindowAsync(IntPtr hWnd, int cmdShow);
[DllImport("User32.dll")]
private static extern bool SetForegroundWindow(IntPtr hWnd);
private const int WS_SHOWNORMAL = 1;

[STAThread]
static void Main()
{

Process instance = RunningInstance();
if (instance == null)
{
//First f = new First();
//f.Show();

Application.EnableVisualStyles();
//Application.SetCompatibleTextRenderingDefault(false);
Application.Run(new MainForm());

}
else
{
MessageBox.Show("你已经运行了该程序！");
HandleRunningInstance(instance);

}

}

//不允许有两个程序同时启动

public static Process RunningInstance()
{

Process current = Process.GetCurrentProcess();

Process[] processes = Process.GetProcessesByName(current.ProcessName);

//遍历正在有相同名字运行的例程

foreach (Process process in processes)
{

//忽略现有的例程

if (process.Id != current.Id)
{

//确保例程从EXE文件运行

if (Assembly.GetExecutingAssembly().Location.Replace("/", "//") ==

current.MainModule.FileName)
{

//返回另一个例程实例

return process;

}

}

}

//没有其它的例程，返回Null

return null;

}

public static void HandleRunningInstance(Process instance)
{

//确保窗口没有被最小化或最大化

ShowWindowAsync(instance.MainWindowHandle, WS_SHOWNORMAL);

//设置真实例程为foreground window

SetForegroundWindow(instance.MainWindowHandle);

}

}
}