UFT Pro (LeanFT) .NET SDK Reference, Version 14.03
FireEvent Method (IWebElement)
Example 
The event info describing the event to trigger. The event can be any HTML DOM event.
Triggers the specified event on this object.
Remarks
Use the EventInfoFactory static class to generate the eventInfo argument value.
Syntax
void FireEvent( 
   EventInfo eventInfo
)

Parameters

eventInfo
The event info describing the event to trigger. The event can be any HTML DOM event.
Example
var search = browser.Describe<IEditField>(new EditFieldDescription
{
    Name = "q"
});
search.FireEvent(EventInfoFactory.CreateEventInfo("onkeydown"));