Adding Handler using 'AddressOf'

Question

When trying to add an event handler to a dynamically created button I get an an error:

Dim Itm As New Button
Itm.Name = "Itm" & i
Itm.Height = 62
Itm.Width = 159
Itm.Text = Temp(i, 0).ToUpper
Itm.Left = (F * 165)
Itm.Visible = True
Itm.BackColor = Colour
Itm.ForeColor = Color.Black
AddHandler Itm.Click, AddressOf Me.Itm_Click
Me.pnlItemButton1.Controls.Add(Itm)
i = i + 1
If i > Temp.Length - 1 Then
    GoTo Exit1
End If

I get an error on the AddressOf line:

"Item_Click is not a member of windowsapplication1.main"

I feel this is because I have set the name to be "Itm" & i but using AddressOf Me.Itm(i)_Click also presents an error. Any thoughts?

Answer 1

You have to declare the event handler Itm_Click and it must be accessible.

For example (presuming that your array Temp exists somewhere):

Public Class Demo
    Protected Sub Itm_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) 

    End Sub

    Public Sub DemoMethod()
        For i As Int32 = 1 To Temp.Length - 1
            Dim Itm As New System.Windows.Forms.Button()
            Itm.Name = "Itm" & i
            Itm.Height = 62
            Itm.Width = 159
            Itm.Text = Temp(i, 0).ToUpper
            Itm.Left = (F * 165)
            Itm.Visible = True
            Itm.BackColor = Colour.White
            Itm.ForeColor = Color.Black
            AddHandler Itm.Click, AddressOf Me.Itm_Click
            Me.pnlItemButton1.Controls.Add(Itm)
        Next
    End Sub
End Class

You can use this event handler for all dynamically created buttons. You get the button that was clicked from the sender argument:

Protected Sub Itm_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) 
    Dim actualButton = Ctype(sender, System.Windows.Forms.Button)
    Dim name = actualButton.Name
End Sub