asked on

Temporarily Disable EventHandler?

I have a DateTimePicker that I want to do something on it's ValueChanged event, but then I want to change the Value back to 'Yesterday's Date' without firing another event.
I've tried RemoveHandler/AddHandler, but it doesn't seem to work.

Private Sub dtpRequest_ValueChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles dtpRequest.ValueChanged
Dim request As String
request = CStr(dtpRequest.Value.Date)
If lbxRequestedDays.Items.Contains(request) = True Then
MsgBox("This day has already been selected.", vbOKOnly, "Attention")
Else
lbxRequestedDays.Items.Add(request.ToString)
End If
lblDaysOff.Text = lbxRequestedDays.Items.Count.ToString & " days"
lblDaysOff.Refresh()
End Sub

ASKER CERTIFIED SOLUTION

dstanley9

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bramsquad

Actually there are a couple functions that provide this functionality. The RemoveHandler and AddHandler functions removes and adds the association respectively.

Try this code out. If you click button one, you'll get a message box. If you click button two then button one, nothing happens. You can also add AddHandler to reassociate the event.

Public Class Form1
Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
RemoveHandler Button1.Click, AddressOf Button1_Click
End Sub

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
MsgBox("one")
End Sub
End Class

Let me know if you have any questions.

~b

bramsquad

Sorry - you've already tried that...guess I should read the whole question :)

dreinmann

ASKER

Yes, this code will run through twice. If I take out the part with the RemoveHandler and value changing to yesterday, it only runs once:
Private Sub dtpRequest_ValueChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles dtpRequest.ValueChanged
Dim request As String
request = CStr(dtpRequest.Value.Date)
If lbxRequestedDays.Items.Contains(request) = True Then
MsgBox("This day has already been selected.", vbOKOnly, "Attention")
Else
lbxRequestedDays.Items.Add(request.ToString)
End If
RemoveHandler dtpRequest.ValueChanged, AddressOf dtpRequest_ValueChanged
dtpRequest.Value = Now().AddDays(-1).Date
AddHandler dtpRequest.ValueChanged, AddressOf dtpRequest_ValueChanged

lblDaysOff.Text = lbxRequestedDays.Items.Count.ToString & " days"
lblDaysOff.Refresh()
End Sub