Delphi CreateOleObject events

问题:

There is a code:

var 
myobject: OleVariant;
begin
 myobject := CreateOleObject('SomeNamespace.SomeClass');
end;

This COM object has events (for example OnClick). How should I connect to these events without importing TLB?

回答1:

You are working with COM late-binding, so do you need write a lot of code to handle events. this task is not difficult if you know COM, basically do you need follow these steps.

• Create a new object(class) derived from TInterfacedObject that implements IDispatch
• implement the Invoke() function of your new class
• Query for the connection point container (IConnectionpointContainer) and desired connection point.
• sink the connection point using IConnectionPointContainer.FindConnectionPoint
• finally execute the IConnectionPoint.Advise() using your implementation of the IDispatch

you can found examples of this implementation on these links

• How to use an objects event created using createoleobject
• Delphi 5 running powerpoint (example using a late binding object with events)
• Delphi 5 running powerpoint (example using a late binding object with events)

try out these links for more info about COM, late-binding and events

• Automation in Delphi COM Programming
• Supporting automation events in Delphi