Add control at runtime to user control's inner panel

Question

I have a user control that contains 2 panels. Panel1 is the parent for Panel2 so Panel2 is placed inside the Panel1 container. Now, at runtime, I want to add controls to my user control. These new controls must be placed inside Panel2. Addings controls with myUserControl.Controls.Add would normally put the new controls into the user control itself and not inside Panel2. I would like Panel2 to be the default container for all controls that are added to the user control at runtime. How to do this?

Answer 1

You can override OnControlAdded, verify whether the UC Handle is already created (InitiaizeComponent() has already being executed, so all child Controls added in the Designer have already been added to the UC's Controls collection), then add the new Control to Panel2.Controls collection:

Public Class MyUSerControl
    Inherits UserControl

    Protected Overrides Sub OnControlAdded(e As ControlEventArgs)
        If IsHandleCreated AndAlso e.Control IsNot Panel1 Then
            Panel2.Controls.Add(e.Control)
        End If
        MyBase.OnControlAdded(e)
    End Sub
End Class

Or, you could add a public method that performs this action:

Dim btn1 = New Button() With {.Text = "Button1", .Name = "Button1"}
Dim btn2 = New Button() With {.Text = "Button2", .Name = "Button2"}

myUSerControl.AddControls(btn1)
' Or
myUSerControl.AddControls({btn1, btn2})

---

Public Class MyUSerControl
    Inherits UserControl

    Public Sub AddControls(ParamArray newControls As Control())
        Panel2.Controls.AddRange(newControls)
    End Sub
End Class