Classes Class AutomationObject() :queryInterface()

Method AutomationObject():queryInterface() Foundation

Queries a dedicated interface

Syntax 
:queryInterface( <cGUID> ) --> oAutomationObject | NIL
Parameters
<cGUID>
<cGUID> is a string with the length of 38 characters and has the following syntax: {nnnnnnnn-nnnn-nnnn-nnnn-nnnnnnnnnnnn}, where each n represents a character in the range of '0'-'9', 'a'-'f' or 'A'-'F'.
A GUID is a world-wide unique value and is the identifier of an interface.
Return

This method creates and returns an AutomationObject. It is connected to the COM/ActiveX component via the interface whose ID is passed in <cGUID>. If the object executing the method does not support the interface requested, :queryInterface() returns NIL.

Description

If an AutomationObject is created, it is automatically connected to a COM/ActiveX component. Subsequently, the application can use the AutomationObject to call methods and access properties exposed by the COM/ActiveX component's default COM interface.

However, often COM/ActiveX components also expose methods and properties in additional interfaces. In this case, :queryInterface() must be used to access this functionality. The method creates and returns an AutomationObject that is connected using a specific COM interface. The object can then be used to access methods and properties of the COM/ActiveX component that are exposed by the COM interface.

To create an AutomationObjects that is connected to a certain COM interfaces, :queryInterface() is called with the GUID of the desired interface.

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