CODEWITHSUNDEEP
vb.net
Søren Strøm
Søren Strøm

Reputation: 3

How to Remove EventHandler

I have a problem removing my Handlers

I load data into several textboxes. When loading is done I call this public Sub:

AddDirtyEventSixH5Why(Group6H5Why) 

Public Sub AddDirtyEventSixH5Why(ByVal ctrl As Control)

    For Each c As Control In ctrl.Controls
        If TypeOf c Is KryptonTextBox Then
            Dim tb As KryptonTextBox = CType(c, KryptonTextBox)
            If tb.Tag <> "NoCheck" Then AddHandler tb.TextChanged, AddressOf SetSixH5WhyDirty
        End If

        If c.Controls.Count > 0 Then
            AddDirtyEventSixH5Why(c)
        End If
    Next

End Sub

Private Sub SetSixH5WhyDirty(ByVal sender As System.Object, ByVal e As System.EventArgs)
    With FrmMainPage
        If vLoadingSystem = False And vLoadingActivity = False Then
            .TxtHiddenSixH5WhyStatus.Text = 1
        End If

    End With

End Sub

After working with data I want to remove the handles using a similar procedure.

I do this, but is does not work

Public Sub RemoveDirtyEventSixH5Why(ByVal ctrl As Control)

    For Each c As Control In ctrl.Controls
        If TypeOf c Is KryptonTextBox Then
            Dim tb As KryptonTextBox = CType(c, KryptonTextBox)
            RemoveHandler tb.TextChanged, AddressOf UnSetSixH5WhyDirty
        End If

        If c.Controls.Count > 0 Then
            RemoveDirtyEventSixH5Why(c)
        End If
    Next

End Sub
Private Sub UnSetSixH5WhyDirty(ByVal sender As System.Object, ByVal e As System.EventArgs)
    With FrmMainPage

        .TxtHiddenSixH5WhyStatus.Text = 0

    End With

End Sub

Is there any hope for me? :-)

Upvotes: 0

Views: 50

Answers (2)

Richard
Richard

Reputation: 108995

AddHandler tb.TextChanged, AddressOf SetSixH5WhyDirty

… RemoveHandler tb.TextChanged, AddressOf UnSetSixH5WhyDirty

You can only remove handlers you have added. As you've never added UnSetSixH5WhyDirty you cannot remove that handler.

Try

RemoveHandler tb.TextChanged, AddressOf SetSixH5WhyDirty

Upvotes: 1

A Friend
A Friend

Reputation: 2750

You need to remove the same method you add, like this:

RemoveHandler tb.TextChanged, AddressOf SetSixH5WhyDirty

You also need to be careful that you only add the handler once. If there is a risk of adding multiple identical handlers then you should (possibly) remove the handler before adding it, in the following manner:

If tb.Tag <> "NoCheck" Then 
    RemoveHandler tb.TextChanged, AddressOf SetSixH5WhyDirty
    AddHandler tb.TextChanged, AddressOf SetSixH5WhyDirty
End If

Upvotes: 0

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