I have the following event in a VB2005 User Control:
Public Event ButtonClicked(ByVal Sender As Object, ByVal E As System.EventArgs)
This code in the User Control is the only code that calls the event:
Private Sub HandleButtons(ByVal Sender As Object, ByVal E As System.EventArgs) Handles btnFirst.Click, btnLast.Click, btnNext.Click, btnPrev.Click
Dim BTN As Button = DirectCast(Sender, Button)
Select Case BTN.Name
Case "btnFirst"
CurrentRecord = 1
Case "btnLast"
CurrentRecord = RecordCount
Case "btnNext"
CurrentRecord += 1
Case "btnPrev"
CurrentRecord -= 1
End Select
RaiseEvent ButtonClicked(Sender, E)
End Sub
I added the User control to a form (FORM1) and add the following code:
Private Sub Form1_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
With NavControl1
.RecordCount = 10
.CurrentRecord = 1
End With
End Sub
Private Sub HandleButtons(ByVal Sender As Object, ByVal E As EventArgs) Handles NavControl1.ButtonClicked
Dim CTRL As Control = DirectCast(Sender, Control)
Dim strBTN As String = String.Empty
Select Case CTRL.Name
Case "btnFirst"
strBTN = "FIRST"
Case "btnLast"
strBTN = "LAST"
Case "btnNext"
strBTN = "NEXT"
Case "btnPrev"
strBTN = "PREVIOUS"
End Select
MessageBox.Show(String.Format("The {0} button was clicked", strBTN))
End Sub
FORM1 runs without any problems. If I remove the code from FORM1 and inherit a new form (FORM2) from FORM1 and add the same code to FORM2 I get an error “Button Click event is read only and can not be changed” when I attempt to open FORM2 in the designer.
Can anyone see what’s causing the problem What can I do to correct it
Inheritance/user control problem
Chris Lerew
Make sure that the accessibility for NavControl1 is Public, Friend, or Protected.
Hope that helps,
Martin Skibye
I have to admit that I don't know enough about event inheritance to really give a good answer. Seeing an error message from trying to implement the ButtonClicked event handler in Form2 kinda made sense: you can only inherit the events the the base form raises.
So I tried to rework it by having the UserControl raise an event in Form1:
Public Class Form1
Public Event ButtonClicked2(ByVal Sender As Object, ByVal E As System.EventArgs)
Private Sub UserControl11_ButtonClicked(ByVal Sender As Object, ByVal E As System.EventArgs) Handles UserControl11.ButtonClicked
RaiseEvent ButtonClicked2(Sender, E)
End Sub
End Class
Public Class Form2
Inherits Form1
Private Sub Form2_ButtonClicked(ByVal Sender As Object, ByVal E As System.EventArgs) Handles MyBase.ButtonClicked2
Debug.Print("Click")
End Sub
End Class
No "Click"....
Sushil Chordia - MSFT
try using the overridable attribute especially if you are going to want to change the code in the inherited form:
Private Overridable Sub HandleButtons....
meetshums
Try changing the way you declare the event. Since this is a standard format event handler, declare it as such:
Instead of:
Public Event ButtonClicked(ByVal Sender As Object, ByVal E As System.EventArgs)
Try:
Public Event ButtonClicked As EventHandler
HTH
Liqun
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