Programmatically show tooltip in winforms application

Question

How can I programatically cause a control\'s tooltip to show in a Winforms app without needing the mouse to hover over the control? (P/Invoke is ok if necessary).

Answer 1

This is the code I use:

static HWND hwndToolTip = NULL;

void CreateToolTip( HWND hWndControl, TCHAR *tipText )
{  
    BOOL success;

  if( hwndToolTip == NULL )
  {
    hwndToolTip = CreateWindow(  TOOLTIPS_CLASS, 
                                 NULL, 
                                 WS_POPUP | TTS_NOPREFIX | TTS_ALWAYSTIP,                                     
                                 CW_USEDEFAULT, CW_USEDEFAULT, 
                                 CW_USEDEFAULT, CW_USEDEFAULT,                                     
                                 NULL, NULL,
                                 hInstResource, 
                                 NULL ); 
  }

  if( hwndToolTip )
  { 
    TOOLINFO ti; 

    ti.cbSize   = sizeof(ti); 
    ti.uFlags   = TTF_TRANSPARENT | TTF_SUBCLASS; 
    ti.hwnd     = hWndControl; 
    ti.uId      = 0; 
    ti.hinst    = NULL; 
    ti.lpszText = tipText; 

    GetClientRect( hWndControl, &ti.rect ); 

    success = SendMessage( hwndToolTip, TTM_ADDTOOL, 0, (LPARAM) &ti ); 
  }
}

Call CreateToolTip function to create a tool tip for a certain control.