using System.Runtime.InteropServices;
using System.Diagnostics;
using System.Reflection;
//*****************************************************
 static class Program
  {
    /// <summary>
    /// 該函數(shù)設(shè)置由不同線程產(chǎn)生的窗口的顯示狀態(tài)。
    /// </summary>
    /// <param name="hWnd">窗口句柄</param>
    /// <param name="cmdShow">指定窗口如何顯示。查看允許值列表，請(qǐng)查閱ShowWlndow函數(shù)的說(shuō)明部分。</param>
    /// <returns>如果函數(shù)原來(lái)可見(jiàn)，返回值為非零；如果函數(shù)原來(lái)被隱藏，返回值為零。</returns>
    [DllImport("User32.dll")]
    private static extern bool ShowWindowAsync(IntPtr hWnd, int cmdShow);
    /// <summary>
    /// 該函數(shù)將創(chuàng)建指定窗口的線程設(shè)置到前臺(tái)，并且激活該窗口。鍵盤(pán)輸入轉(zhuǎn)向該窗口，并為用戶改各種可視的記號(hào)。系統(tǒng)給創(chuàng)建前臺(tái)窗口的線程分配的權(quán)限稍高于其他線程。
    /// </summary>
    /// <param name="hWnd">將被激活并被調(diào)入前臺(tái)的窗口句柄。</param>
    /// <returns>如果窗口設(shè)入了前臺(tái)，返回值為非零；如果窗口未被設(shè)入前臺(tái)，返回值為零。</returns>
    [DllImport("User32.dll")]
    private static extern bool SetForegroundWindow(IntPtr hWnd);
    private const int WS_SHOWNORMAL = 1;

    /// <summary>
    /// 應(yīng)用程序的主入口點(diǎn)。
    /// </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>
    /// 獲取正在運(yùn)行的實(shí)例，沒(méi)有運(yùn)行的實(shí)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>
    /// 顯示已運(yùn)行的程序。
    /// </summary>
    public static void HandleRunningInstance(Process instance)
    {
      ShowWindowAsync(instance.MainWindowHandle, WS_SHOWNORMAL); //顯示，可以注釋掉
      SetForegroundWindow(instance.MainWindowHandle);      //放到前端
    }
  }

//=====創(chuàng)建互斥體法：=====
bool blnIsRunning;
Mutex mutexApp = new Mutex(false, Assembly.GetExecutingAssembly().FullName, out  blnIsRunning);
if (!blnIsRunning)
{
  MessageBox.Show("程序已經(jīng)運(yùn)行！", "提示",
  MessageBoxButtons.OK, MessageBoxIcon.Exclamation);
  return;
}  



//保證同時(shí)只有一個(gè)客戶端在運(yùn)行  
System.Threading.Mutex mutexMyapplication = new System.Threading.Mutex(false, "OnePorcess.exe");
if (!mutexMyapplication.WaitOne(100, false))
{
  MessageBox.Show("程序" + Application.ProductName + "已經(jīng)運(yùn)行！", Application.ProductName,
  MessageBoxButtons.OK, MessageBoxIcon.Error);
  return;
}


//=====判斷進(jìn)程法：(修改程序名字后依然能執(zhí)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("程序已經(jīng)運(yùn)行！", Application.ProductName,
      MessageBoxButtons.OK, MessageBoxIcon.Exclamation);
      return;
    }
  }
}

static void Main() 
{ 
  bool createNew; 
  using (System.Threading.Mutex m = new System.Threading.Mutex(true, Application.ProductName, out createNew)) 
  { 
    if (createNew) 
    { 
      Application.EnableVisualStyles(); 
      Application.SetCompatibleTextRenderingDefault(false); 
      Application.Run(new Form1()); 
    } 
    else 
    { 
      MessageBox.Show("Only one instance of this application is allowed!"); 
    } 
  } 
}
Boolean createdNew; //返回是否賦予了使用線程的互斥體初始所屬權(quán)
System.Threading.Mutex instance = new System.Threading.Mutex(true, "MutexName", out createdNew); //同步基元變量
if (createdNew) //賦予了線程初始所屬權(quán)，也就是首次使用互斥體
{
Application.Run(new Form1()); /s/這句是系統(tǒng)自動(dòng)寫(xiě)的
instance.ReleaseMutex();
}
else
{
MessageBox.Show("已經(jīng)啟動(dòng)了一個(gè)程序，請(qǐng)先退出！","系統(tǒng)提示",MessageBoxButtons.OK,MessageBoxIcon.Error);
Application.Exit();
}

Process.Start(Process.GetCurrentProcess().ProcessName + ".exe");
Application.Exit();

Process.Start(Process.GetCurrentProcess().ProcessName + ".exe");
Application.Exit();