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RemoveHandler Statement

  • Άρθρο

Removes the association between an event and an event handler.

Syntax

RemoveHandler event, AddressOf eventhandler

Parts

Term Definition
event The name of the event being handled.
eventhandler The name of the procedure currently handling the event.

Remarks

The AddHandler and RemoveHandler statements allow you to start and stop event handling for a specific event at any time during program execution.

Note

For custom events, the RemoveHandler statement invokes the event's RemoveHandler accessor. For more information on custom events, see Event Statement.

Example

Sub TestEvents()
    Dim Obj As New Class1
    ' Associate an event handler with an event.
    AddHandler Obj.Ev_Event, AddressOf EventHandler
    ' Call the method to raise the event.
    Obj.CauseSomeEvent()
    ' Stop handling events.
    RemoveHandler Obj.Ev_Event, AddressOf EventHandler
    ' This event will not be handled.
    Obj.CauseSomeEvent()
    ' Associate an event handler with an event, using a lambda.
    ' This handler cannot be removed.
    AddHandler Obj.Ev_Event, Sub ()
        MsgBox("Lambda caught event.")
    End Sub
    ' This event will be handled by the lambda above.
    Obj.CauseSomeEvent()
End Sub

Sub EventHandler()
    ' Handle the event.
    MsgBox("EventHandler caught event.")
End Sub

Public Class Class1
    ' Declare an event.
    Public Event Ev_Event()
    Sub CauseSomeEvent()
        ' Raise an event.
        RaiseEvent Ev_Event()
    End Sub
End Class

See also