单实例运行

一、

using System;
using System.Runtime.InteropServices;
using System.Windows.Forms;
using System.Diagnostics;
using System.Reflection;

public class OneInstnace
{

//Api声明，并声明一

[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] public static void Main()
{
  //得到正在运行的例程
  Process instance = RunningInstance();
  if (instance == null)
  {
   //如果没有其它例程，就新建一个窗体
   Application.Run (new OneInstnace());
  }
  else
  {
   //处理发现的例程
   HandleRunningInstance(instance);
  }
}
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);
}
}

二、

/// <summary>
/// 单实例运行
/// </summary>
/// <returns> true 应用程序已启动，false 则没有 </returns>
public bool SingleRun(ref System.Threading.Mutex mutex )
{
    mutex = new System.Threading.Mutex(false, "WINDOWS");
    if (!mutex.WaitOne(0, false))
    {
        mutex.Close();
        mutex = null;
    }
    if (mutex == null)
    {
        return true;
    }
    return false;
}