Question

I have a Windows Service written in Delphi which runs a number of programs.

On Stopping the service, I want to also close these programs. When the service was originally written, this worked fine, but I think I’ve updated the tProcess component and now – The subordinate programs are not being closed.

in tProcess – Here’s the code which starts the new processes.

  if CreateProcess( nil , PChar( FProcess.Command ) , nil , nil , False ,     NORMAL_PRIORITY_CLASS , nil , Directory ,     StartupInfo , ProcessInfo ) then     begin       if FProcess.Wait then         begin           WaitForSingleObject( ProcessInfo.hProcess , Infinite );           GetExitCodeProcess( ProcessInfo.hProcess , ExitCode );           if Assigned( FProcess.FOnFinished ) then             FProcess.FOnFinished( FProcess , ExitCode );         end;       CloseHandle( ProcessInfo.hProcess );       CloseHandle( ProcessInfo.hThread );     end; 

Each of the executables called by this are Windows GUI Programs (With a close button at the top).

When I stop the service, I also want to stop (not kill) the programs I’ve started up via the createProcess procedure.

How would you do this?

Answer 1

You want to enumerate open windows that match your launched ProcessId and tell those windows to close. Here’s some sample code for that:

uses Windows;  interface     function MyTerminateAppEnum(hHwnd:HWND; dwData:LPARAM):Boolean; stdcall;  implementation  function MyTerminateAppEnum(hHwnd:HWND; dwData:LPARAM):Boolean;  var      vID:DWORD;  begin      GetWindowThreadProcessID(hHwnd, @vID);      if vID = dwData then      begin     PostMessage(hHwnd, WM_CLOSE, 0, 0); //tell window to close gracefully     Result := False;  //can stop enumerating       end      else      begin     Result := TRUE;  //keep enumerating until you find your id      end;  end; 

Then you’ll want to utilize this in your code when you want to shut down the launched applications:

Procedure TerminateMe(YourSavedProcessInfo:TProcessInformation); var   vExitCode:UINT; begin   GetExitCodeProcess(YourSavedProcessInfo.hProcess, vExitCode);   if (vExitCode = STILL_ACTIVE) then  //launched app still running..   begin     //tell it to close     EnumWindows(@MyTerminateAppEnum, YourSavedProcessInfo.dwProcessId);      if WaitForSingleObject(YourSavedProcessInfo.hProcess, TIMEOUT_VAL) <> WAIT_OBJECT_0 then     begin       if not TerminateProcess(YourSavedProcessInfo.hProcess, 0) then  //didn't close, try to terminate       begin          //uh-oh   Didn't close, didn't terminate..       end;     end;   end;   CloseHandle(YourSavedProcessInfo.hProcess);   CloseHandle(YourSavedProcessInfo.hThread); end;