C # Only One winform process can be run

Using system;

Using system. Collections. Generic;

Using system. LINQ;

Using system. Windows. forms;

Using system. diagnostics;

Using system. runtime. interopservices;

Using system. reflection;

 

Namespace onLyprocess

{

Static class Program

{

[Stathread]

Static void main ()

{

MessageBox. Show ("ddddd ");

Process instance = runninginstance ();

If (instance = NULL)

{

System. Windows. Forms. application. enablevisualstyles (); // these two rows allow the form to have the XP style.

System. Windows. Forms. application. doevents ();

Application. Run (New form1 ());

}

Else

{

Handlerunninginstance (instance );

}

}

 

# Region only runs one instance

Public static process runninginstance ()

{

Process current = process. getcurrentprocess (); // the current new thread

Process [] processes = process. getprocessesbyname (current. processname );

// Traverse the process list with the same name as the current process

Foreach (Process in processes)

{

// Process. The original thread ID is different from the current new thread ID.

// 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; // return the form of the original thread

}

}

}

Return NULL;

}

Private Static void handlerunninginstance (process instance)

{

MessageBox. Show ("this application system is already running! "," Message ", messageboxbuttons. OK, messageboxicon. information );

Showwindowasync (instance. main1_whandle, ws_shownormal); // call the API function and display the window normally.

Setforegroundwindow (instance. main1_whandle); // place the window at the front end.

}

[DllimpORT ("user32.dll")]

Private Static extern bool showwindowasync (system. intptr hwnd, int cmdshow );

[DllimpORT ("user32.dll")]

Private Static extern bool setforegroundwindow (system. intptr hwnd );

Private const int ws_shownormal = 1;

# Endregion

}

}