If a context menu gesture was recognized, a WM_CONTEXTMENUmessage will be sent to shrg->hwndClientand propagated up the parent chain if not handled. In addition, one of the following actions will be taken based on the value of shrg->dwFlags:

• If shrg->dwFlagsis SHRG_RETURNCMD, the function will return GN_CONTEXTMENUnotification message. If an application uses this flag, it should be aware that bringing up context menus in direct response to the return value makes those menus inaccessible to hardware navigation. To enable hardware navigation, the application should do context menu handling in response to WM_CONTEXTMENU (see Remarkssection below).
  
  
• If shrg->dwFlagsis SHRG_NOTIFYPARENT, a WM_NOTIFYmessage with GN_CONTEXTMENU set will be sent to the parent of shrg->hwndClient. The function will return the return value that came from processing the WM_NOTIFY message.
  
  
• If shrg->dwFlagsis SHRG_LONGDELAY, a WM_NOTIFY message with GN_CONTEXTMENU set will be sent to shrg->hwndClient, and the function will return the return value that came from processing the WM_NOTIFY message.
  
  

This function returns 0 if there was no context menu gesture.

The only gesture currently supported is for context menus, where a context menu gesture is defined as a user tapping on the screen and holding the stylus in the same spot for some amount of time, or the user pressing and holding the action button for some amount of time. This amount of time can be controlled by the OEM through a registry setting.

Typically, a control will call this function during the WM_LBUTTONDOWNprocessing (for tap and hold recognition) or during the WM_KEYDOWNprocessing (for action press and hold recognition). If a gesture is recognized messages are sent to the application as specified in the Return Values section, and it is the responsibility of the application to bring up the context menu in response to the messages sent.

Applications should do context menu handling in response to WM_CONTEXTMENU whenever possible to ensure proper hardware navigation behavior. The GN_CONTEXTMENU notification should be used by the application only when the extra information provided by this message is needed.

If you do not want to provide the standard animation feedback for a tap-and-hold gesture, set the SHRG_NOANIMATION flag when calling the SHRecognizeGesturefunction. The following code example shows this setting.

	Copy Code
case WM_LBUTTONDOWN: { SHRGINFO shrg; HMENU hmenu; shrg.cbSize = sizeof(shrg); shrg.hwndClient = hWnd; shrg.ptDown.x = LOWORD(lParam); shrg.ptDown.y = HIWORD(lParam); shrg.dwFlags = SHRG_RETURNCMD SHRG_NOANIMATION; if (SHRecognizeGesture(&shrg) == GN_CONTEXTMENU) { hmenu = GetSubMenu(g_hMainMenu, 0); TrackPopupMenuEx(hmenu, TPM_LEFTALIGN, LOWORD(lParam), HIWORD(lParam), hWnd, NULL); } break; }