保证应用程序只有一个实例在运行

[C#]

public static Process RunningInstance()

{

Process current = Process.GetCurrentProcess();

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

//Loop through the running processes in with the same name

foreach (Process process in processes)

{

//Ignore the current process

if (process.Id != current.Id)

{

//Make sure that the process is running from the exe file.

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

{

//Return the other process instance.

return process;

}

}

}

//No other instance was found, return null.

return null;

}

[VB.NET]

Public Shared Function RunningInstance() As Process

Dim current As Process = Process.GetCurrentProcess()

Dim processes As Process() = Process.GetProcessesByName(current.ProcessName)

'Loop through the running processes in with the same name

Dim process As Process

For Each process In processes

'Ignore the current process

If process.Id <> current.Id Then

'Make sure that the process is running from the exe file.

If [Assembly].GetExecutingAssembly().Location.Replace("/", "/") = current.MainModule.FileName Then

'Return the other process instance.

Return process

End If

End If

Next process

'No other instance was found, return null.

Return Nothing

End Function 'RunningInstance

如果检测到已有窗体实例,将此实例显示出来参考:

[STAThread] static void Main() {        //Get the running instance.        Process instance = RunningInstance();        if (instance == null)        {               //There isn't another instance, show our form.               Application.Run (new Form2());        }        else        {               //There is another instance of this process.               HandleRunningInstance(instance);        } } public static Process RunningInstance() {        Process current = Process.GetCurrentProcess();        Process[] processes = Process.GetProcessesByName (current.ProcessName);        //Loop through the running processes in with the same name        foreach (Process process in processes)        {               //Ignore the current process               if (process.Id != current.Id)               {                      //Make sure that the process is running from the exe file.                      if (Assembly.GetExecutingAssembly().Location.Replace("/", "//") ==current.MainModule.FileName)                      {                             //Return the other process instance.                             return process;                      }               }        }        //No other instance was found, return null.        return null; } public static void HandleRunningInstance(Process instance) {        //Make sure the window is not minimized or maximized        ShowWindowAsync (instance.MainWindowHandle , WS_SHOWNORMAL);        //Set the real intance to foreground window        SetForegroundWindow (instance.MainWindowHandle); } [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