How to code "one sub for many subs" in VB.NET?

Question

I have n Labels on Form, e.g: Label1, Label2,..., Labeln. Normally, when I write Click event for all Labels:

    Private Sub Label1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Label1.Click
        Msgbox "1"
    End Sub

Private Sub Label2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Label2.Click
    Msgbox "2"
End Sub

Private Sub Labeln_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Labeln.Click
    Msgbox "n"
End Sub

Writting is very complex when n is large!

Now, I want to write the code simply to click to Lablei and generate "i" (one proceduce to many proceduces). How to handle it? Thanks in advance.

Answer 1

Private Sub Labeln_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) _
       Handles Label1.Click, Label2.Click, Label3.Click '...
    Dim l As Label = DirectCast(sender, Label)
    Msgbox l.Name
End Sub

If n is very large, skip the Handles portion of the method and do this in your form load:

For Each l As Label in Me.Controls.OfType(Of Label)()
    AddHandler l.Click, AddressOf Labeln_Click
Next

Answer 2

You can dynamically assign the event handlers when you create your labels using AddHandler:

Sub test()
    Dim label1 As New Label()
    AddHandler label1.Click, AddressOf HandleLabelClick
    Me.Controls.Add(label1)
End Sub

Here's the event handler:

Sub HandleLabelClick(ByVal sender As System.Object, ByVal e As System.EventArgs)
    MsgBox(DirectCast(sender, Label).Name)
End Sub