WebBroser之IViewObject Interface

IID_IViewObject

{0000010D-0000-0000-C000-000000000046}

 

The IViewObject interface enables an object to display itself directly without passing a data object to the caller. In addition, this interface can create and manage a connection with an advise sink so the caller can be notified of changes in the view object.   The caller can request specific representations and specific target devices. For example, a caller can ask for either an object's content or an iconic representation. Also, the caller can ask the object to compose a picture for a target device that is independent of the drawing device context. As a result, the picture can be composed for one target device and drawn on another device context. For example, to provide a print preview operation, you can compose the drawing for a printer target device but actually draw the representation on the display.   The IViewObject interface is similar to IDataObject; except that IViewObject places a representation of the data onto a device context while IDataObject places the representation onto a transfer medium.   Unlike most other interfaces, IViewObject cannot be marshaled to another process. This is because device contexts are only effective in the context of one process.   You call IViewObject from a container application if you need to draw a contained object on a specific device context. For example, if you want to print the object to a printer, you call the Draw method in the IViewObject interface.

 

Methods in VTable order
IUnknown Methods	Description
QueryInterface	Returns pointers to supported interfaces.
AddRef	Increments reference count.
Release	Decrements reference count.
IViewObject Methods	Description
Draw	Draws a representation of the object onto a device context.
GetColorSet	Returns the logical palette the object uses for drawing.
Freeze	Freezes the drawn representation of an object so it will not change until a subsequent Unfreeze.
Unfreeze	Unfreezes the drawn representation of an object.
SetAdvise	Sets up a connection between the view object and an advise sink so that the advise sink can receive notifications of changes in the view object.
GetAdvise	Returns the information on the most recent SetAdvise.

 

Draw

FUNCTION IViewObject_Draw ( _   BYVAL pthis AS DWORD PTR, _   BYVAL dwDrawAspect AS DWORD, _   BYVAL lindex AS LONG, _   BYVAL pvAspect AS DWORD, _   BYREF ptd AS DVTARGETDEVICE, _   BYVAL hdcTargetDev AS DWORD, _   BYVAL hdcDraw AS DWORD, _   BYREF lprcBounds AS RECTL, _   BYREF lprcWBounds AS RECTL, _   BYVAL pfnContinue AS DWORD, _   BYVAL dwContinue AS DWORD _   ) AS LONG   LOCAL HRESULT AS LONG   CALL DWORD @@pthis[3] USING IViewObject_Draw (pthis, dwDrawAspect, lIndex, pvAspect, ptd, hdcTargetDev, hdcDraw, lprcBounds, lprcWBounds, pfnContinue, dwContinue) TO HRESULT   FUNCTION = HRESULT END FUNCTION

 

GetColorSet

FUNCTION IViewObject_GetColorSet ( _   BYVAL pthis AS DWORD PTR _ , BYVAL dwAspect AS DWORD _ , BYVAL lindex AS LONG _ , BYVAL pvAspect AS DWORD _ , BYREF ptd AS DVTARGETDEVICE _ , BYVAL hdcTargetDev AS DWORD _ , BYREF ppColorSet AS DWORD _   ) AS LONG     LOCAL HRESULT AS LONG   CALL DWORD @@pthis[4] USING IViewObject_GetColorSet (pthis, dwAspect, lIndex, pvAspect, ptd, hdcTargetDev, ppColorSet) TO HRESULT   FUNCTION = HRESULT END FUNCTION

 

Freeze

FUNCTION IViewObject_Freeze ( _   BYVAL pthis AS DWORD PTR _ , BYVAL dwAspect AS DWORD _ , BYVAL lindex AS LONG _ , BYVAL pvAspect AS DWORD _ , BYREF pdwFreeze AS DWORD _   ) AS LONG     LOCAL HRESULT AS LONG   CALL DWORD @@pthis[5] USING IViewObject_Freeze (pthis, dwAspect, lIndex, pvAspect, pdwFreeze) TO HRESULT   FUNCTION = HRESULT END FUNCTION

 

Unfreeze

FUNCTION IViewObject_Unfreeze ( _   BYVAL pthis AS DWORD PTR _ , BYVAL dwFreeze AS DWORD _   ) AS LONG     LOCAL HRESULT AS LONG   CALL DWORD @@pthis[6] USING IViewObject_Unfreeze (pthis, dwFreeze) TO HRESULT   FUNCTION = HRESULT END FUNCTION

 

SetAdvise

FUNCTION IViewObject_SetAdvise ( _   BYVAL pthis AS DWORD PTR _ , BYVAL aspects AS DWORD _ , BYVAL advf AS DWORD _ , BYVAL pAdvSink AS DWORD _   ) AS LONG     LOCAL HRESULT AS LONG   CALL DWORD @@pthis[7] USING IViewObject_SetAdvise (pthis, aspects, advf, pAdvSink) TO HRESULT   FUNCTION = HRESULT END FUNCTION

 

GetAdvise

FUNCTION IViewObject_GetAdvise ( _   BYVAL pthis AS DWORD PTR _ , BYREF aspects AS DWORD _ , BYREF advf AS DWORD _ , BYREF ppAdvSink AS DWORD _   ) AS LONG     LOCAL HRESULT AS LONG   CALL DWORD @@pthis[8] USING IViewObject_GetAdvise (pthis, aspects, advf, ppAdvSink) TO HRESULT   FUNCTION = HRESULT END FUNCTION

 引自：http://www.com.it-berater.org/COM/ole_and_data_transfer/interfaces/IViewObject.htm