Using an event name with return type and arguments

The following description uses the first syntax. The class has two events, onclick and ondoubleclick:

PBXEXPORT LPCTSTR PBXCALL PBX_GetDescription()
{
   static const TCHAR desc[] = {
      "class visualext from userobject\n"
      "event int onclick()\n"
      "event int ondoubleclick()\n"
      "subroutine setcolor(int r, int g, int b)\n"
      "subroutine settext(string txt)\n"
      "end class\n" 
   };
return desc;
}

Capturing messages and mouse clicks

The code in the extension captures the Windows messages that cause the window to be drawn, as well as mouse clicks and double clicks:

LRESULT CALLBACK CVisualExt::WindowProc(
                                   HWND hwnd,
                                   UINT uMsg,
                                   WPARAM wParam,
                                   LPARAM lParam
                                   )
{
   CVisualExt* ext = (CVisualExt*)::GetWindowLong(hwnd,
      GWL_USERDATA);
   switch(uMsg) {

   case WM_CREATE:
      return 0;

   case WM_SIZE:
      return 0;

   case WM_COMMAND:
      return 0;

   case WM_PAINT: {
      PAINTSTRUCT ps;
      HDC hdc = BeginPaint(hwnd, &ps);
      RECT rc;
      GetClientRect(hwnd, &rc);
      LOGBRUSH lb;
      lb.lbStyle = BS_SOLID;
 
// Get color using the visual class’s GetColor method
      lb.lbColor = ext->GetColor();
      HBRUSH hbrush = CreateBrushIndirect(&lb);
      HBRUSH hbrOld = (HBRUSH)SelectObject(hdc,
         hbrush);
      Rectangle(hdc, rc.left, rc.top, rc.right-rc.left,
         rc.bottom-rc.top);
      SelectObject(hdc, hbrOld);
      DeleteObject(hbrush);

// Get text using the visual class’s GetText method
      DrawText(hdc, ext->GetText(), 
         ext->GetTextLength(), &rc, 
      DT_CENTER|DT_VCENTER|DT_SINGLELINE);
      EndPaint(hwnd, &ps);
      }
      return 0;

// Trigger event scripts in the PowerBuilder application
   case WM_LBUTTONUP:
      ext->TriggerEvent("onclick");
      break;

   case WM_LBUTTONDBLCLK:
      ext->TriggerEvent("ondoubleclick");
      break;
   }
   return DefWindowProc(hwnd, uMsg, wParam, lParam);
}

Triggering click events

The following is the TriggerEvent method that triggers the Onclick and Ondoubleclick events:

void CVisualExt::TriggerEvent(LPCTSTR eventName)
{
   pbclass clz = d_session->GetClass(d_pbobj);
   pbmethodID mid = d_session->GetMethodID(clz,
      eventName, PBRT_EVENT, "I");

   PBCallInfo ci;
   d_session->InitCallInfo(clz, mid, &ci);
   d_session->TriggerEvent(d_pbobj, mid, &ci);
   d_session->FreeCallInfo(&ci);
}