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.
The IViewObject interface has these methods.
|IViewObject::Draw||Draws a representation of an object onto the specified device context.|
|IViewObject::Freeze||Freezes the drawn representation of an object so that it will not change until the IViewObject::Unfreeze method is called. The most common use of this method is for banded printing.|
|IViewObject::GetAdvise||Retrieves the advisory connection on the object that was used in the most recent call to IViewObject::SetAdvise.|
|IViewObject::GetColorSet||Returns the logical palette that the object will use for drawing in its IViewObject::Draw method with the corresponding parameters.|
|IViewObject::SetAdvise||Establishes a connection between the view object and an advise sink so that the advise sink can be notified about changes in the object's view.|
|IViewObject::Unfreeze||Releases a drawing that was previously frozen using IViewObject::Freeze. The most common use of this method is for banded printing.|
|Minimum supported client||Windows 2000 Professional [desktop apps only]|
|Minimum supported server||Windows 2000 Server [desktop apps only]|