How to handle ihtmldocument2.onmouseover event in. net

Some ActiveX controls use the default method of the idispatch interface to implement the event mechanism. How to use such Event Callback in. Net?
1 )? Define a class, define the event processing method, and add It is the default method of the idispatch interface of this class. The following is an example:
Public class InterOP
Public sub onmouseover ()
MessageBox. Show ("Mouseover ")
End sub
End Class

2) But if you write
Ihtmldocument2 Doc = axwebbrowser1.document
Doc. onmouseover = new InterOP
Then, a not_implemented exception will be generated during the runtime, because by default, InterOP uploaller of. NET will convert marshal into variant of the vt_unknown type, and we need to convert the marshal into Variant of vt_dispatch. We can use disptachwrapper provided by. Net to solve this problem.
Doc. onmouseover = new dispatchwrapper (New InterOP)
When you no longer need to handle this event, you can use the following method to disconnect the event handler.
Doc. onmouseover = new dispatchwrapper (nothing)