From Appmethod Libraries
Jump to: navigation, search

Object Pascal

function QueryInterface(const IID: TGUID; out Obj): HResult; virtual; stdcall;


virtual HRESULT __stdcall QueryInterface(const GUID &IID, /* out */ void *Obj);


Type Visibility Source Unit Parent
function protected
System.Classes TComponent


Returns a reference to a specified interface if the current component supports that interface.

QueryInterface checks whether the component supports the interface specified by IID and, if so, returns a reference to that interface as the Obj parameter. If the component does not support the interface, the Obj parameter returns nil (Object Pascal) or NULL (C++).

QueryInterface returns the S_OK execution code on success. HResult type defines the following execution codes: S_OK, S_FALSE, E_NOINTERFACE, E_UNEXPECTED, and E_NOTIMPL.

Note: For components that act as COM object wrappers, QueryInterface calls the QueryInterface method of the internal COM object.

See Also