[RESOLVED] [2005] Mutually Aware Controls

[FourBlades]

Let's say I make a user control that is a composite of just a single Button control. Now I place two of those on a form.
Say, at runtime, I wanted to be able to change the backcolor of one control and have the other control pick up on the BackColor changed event of the first control and also change it's backcolor to match the first control's backcolor (just an example).

But I don't want to handle the event in the using application. I want the controls themselves to listen for and pick up on the event sent by other controls of the same type.

Is it possible to have one control listen for events that another control raises?

Thanks

[FourBlades]

Ok, yes it works.
Each control just has to maintain a list of it's "sibling" controls and add a handler for each sibling control's event.
When the sibling raises an event it's "sister controls" pick up the event.
So this allows controls to communicate with each other independent of code in the using application.

I guess I should have known this to begin with...but now I know for sure

[jmcilhinney]

You only need one collection, e.g.

Public Class UserControl1
 
    Private Shared instances As New List(Of UserControl1)
 
    Public Sub New()
        ' This call is required by the Windows Form Designer.
        InitializeComponent()
 
        ' Add any initialization after the InitializeComponent() call.
 
        UserControl1.instances.Add(Me)
    End Sub
 
    Private Sub UserControl1_BackColorChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.BackColorChanged
        For Each instance As UserControl1 In UserControl1.instances
            If instance.BackColor <> Me.BackColor Then
                instance.BackColor = Me.BackColor
            End If
        Next instance
    End Sub
 
    Private Sub UserControl1_Disposed(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Disposed
        UserControl1.instances.Remove(Me)
    End Sub
 
End Class

[FourBlades]

Thanks jm
I should have known that too.
I'll change the code.
Thanks for taking the time.