Switch Case and Menus

I'm learning the Windows API and I have written just a plain program which opens up with a menu on the top, I have created ther menu so that there is a tools button that expands to a button which brings up a message box which then tells you the program directory. This is fine apart from when you close this message box, the whole program quits. This is not what I want. Is there some special piece of code I'm missing or is it my code thats bad I've tried substituting the hwnd in MessageBox() for NULL/0 but it still does the smae thing:

The windows procedure,

Code:

---

LRESULT CALLBACK WndProc( HWND hwnd, UINT Msg, WPARAM wParam, LPARAM lParam )
{
  switch( Msg )
  {
  case WM_COMMAND:
      switch( LOWORD( wParam ) )
      {
      case ID_FILE_EXIT:
        PostMessage( hwnd, WM_CLOSE, 0, 0 );
        break;
      case ID_TOOLS_PROGRAMDIRECTORY:
        {
            HINSTANCE hInstance = GetModuleHandle( NULL );
            char szFileName[MAX_PATH];

            GetModuleFileName( hInstance, szFileName, MAX_PATH );
            MessageBox( hwnd, szFileName, "The Directory Is:", MB_OK );
        }
        break;
      }
  case WM_CLOSE:
      DestroyWindow( hwnd );
      break;
  case WM_DESTROY:
      PostQuitMessage( 0 );
      break;
  default:
      return DefWindowProc( hwnd, Msg, wParam, lParam );
  }
  return 0;
}

---

Found your problem. You missed putting the break; command at the end of the WM_COMMAND case. This causes WM_CLOSE to be called as part of WM_COMMAND so the window will be destroyed every time. Regardless of the button/menu.

EG:

Code:

---

  case WM_COMMAND:
      switch( LOWORD( wParam ) )
      {
      case ID_FILE_EXIT:
        PostMessage( hwnd, WM_CLOSE, 0, 0 );
        break;
      case ID_TOOLS_PROGRAMDIRECTORY:
        {
            HINSTANCE hInstance = GetModuleHandle( NULL );
            char szFileName[MAX_PATH];

            GetModuleFileName( hInstance, szFileName, MAX_PATH );
            MessageBox( hwnd, szFileName, "The Directory Is:", MB_OK );
        }
        break;
      }
      break;

---

Add the break statement after the final bracket "}"

Thanks, problem solved.