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;
        }