Passing Buttons to Procedures

You've got 200 buttons in your new program, and each one has to be initialized with a long series of code statements. Is there some easy way to organize this process? There is—you can pass the buttons to a procedure, and place the initialization code in that procedure.

Here's an example—we can set a button's caption by passing it to a Sub procedure named SetCaption like this:

Private Sub Button1_Click(ByVal sender As System.Object, _
    ByVal e As System.EventArgs) Handles Button1.Click
    SetCaption(Button1)
End Sub

In the SetCaption Sub procedure, I pass the button as an object of class Button, and I pass it by reference; passing it by reference makes it explicit that I want to be able to change the Button object:

Private Sub Button1_Click(ByVal sender As System.Object, _
    ByVal e As System.EventArgs) Handles Button1.Click
    SetCaption(Button1)
End Sub

Private Sub SetCaption(ByRef TargetButton As Button)
        ⋮
End Sub

And in the SetCaption Sub procedure, I can change the Text property of the button, like this:

Private Sub Button1_Click(ByVal sender As System.Object, _
    ByVal e As System.EventArgs) Handles Button1.Click
    SetCaption(Button1)
End Sub

Private Sub SetCaption(ByRef TargetButton As Button)
    TargetButton.Text = "I've been clicked"
End Sub

The result appears in Figure 6.12; when you click the command button, the SetCaption Sub procedure changes its caption, as you see in that figure.

Figure 6.12: Passing a button to a procedure to change its caption.