NM_CUSTOMDRAW

Article
08/28/2006

This message is sent by some common controls to notify their parent windows about drawing operations. The message is sent in the form of a WM_NOTIFY message.

NM_CUSTOMDRAW
#ifdef LIST_VIEW_CUSTOM_DRAW
  lpNMCustomDraw = (LPNMLVCUSTOMDRAW) lParam;
#elif TOOL_TIPS_CUSTOM_DRAW
  lpNMCustomDraw = (LPNMTTCUSTOMDRAW) lParam;
#elif TREE_VIEW_CUSTOM_DRAW
  lpNMCustomDraw = (LPNMTVCUSTOMDRAW) lParam;
#else
  lpNMCustomDraw = (LPNMCUSTOMDRAW) lParam;
#endif

Parameters

lpNMCustomDraw
Long pointer to a custom draw-related structure that contains information about the drawing operation. The following table lists the controls that send the NM_CUSTOMDRAW message and their associated structures.

Control Structure

List view NMLVCUSTOMDRAW

ToolTips NMTTCUSTOMDRAW

Tree view NMTVCUSTOMDRAW

All other supported controls NMCUSTOMDRAW

Control	Structure
List view	NMLVCUSTOMDRAW
ToolTips	NMTTCUSTOMDRAW
Tree view	NMTVCUSTOMDRAW
All other supported controls	NMCUSTOMDRAW

Return Values

The value your application can return depends on the current drawing stage. The dwDrawStage member of the associated NMCUSTOMDRAW structure holds a value that specifies the drawing stage.

You must return one of the following values when dwDrawStage equals CDDS_PREPAINT:

CDRF_DODEFAULT
The control will draw itself. It will not send any additional NM_CUSTOMDRAW messages for this paint cycle.
CDRF_NOTIFYITEMDRAW
The control will notify the parent of any item-related drawing operations. It will send NM_CUSTOMDRAW messages before and after drawing items.
CDRF_NOTIFYITEMERASE
The control will notify the parent when an item will be erased. It will send NM_CUSTOMDRAW messages before and after erasing items.
CDRF_NOTIFYPOSTERASE
The control will notify the parent after erasing an item.
CDRF_NOTIFYPOSTPAINT
The control will notify the parent after painting an item.
CDRF_NOVERTBAR
The control will not draw a vertical separator bar for TBSTYLE_DROPDOWN buttons.

You must return one of the following values when dwDrawStage equals CDDS_ITEMPREPAINT:

CDRF_NEWFONT
Your application specified a new font for the item; the control will use the new font. For more information on changing fonts, see Changing Fonts and Colors.
CDRF_SKIPDEFAULT
Your application drew the item manually. The control will not draw the item.

Remarks

Currently header, list view, rebar, toolbar, ToolTip, trackbar, and tree view controls support custom draw functionality. The ToolTip control supports custom draw for Microsoft® Windows® CE.

Example

case WM_NOTIFY:
   {
       LPNMHDR lpnm = (LPNMHDR) lParam;
       // Check for the dropdown notification
       if (lpnm->hwndFrom == p_stParams->hwndToolBar)
       {
           switch (lpnm->code)
           {
               case NM_CUSTOMDRAW:
               {
                   NMCUSTOMDRAW *pnmcd = (NMCUSTOMDRAW *)lParam;
                   switch (pnmcd->dwDrawStage)
                   {
                       case CDDS_ITEMPREPAINT:
                           if (pnmcd->dwItemSpec == IDM_HEADER_SHOWBY_SUBMENU)
                           {
                               SetWindowLong(hDlg, DWL_MSGRESULT, (LONG)CDRF_NOVERTBAR);
                               return TRUE;
                           }
                           break;
                       default:
                           break;
                   }
               }
               default:
                   break;
           }
       }
   }

Requirements

Pocket PC: Pocket PC 2002 and later.
Smartphone : Smartphone 2002 and later.
OS Versions: Windows CE 2.0 and later.
Header: Commctrl.h.

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