I have a MasterPage and multiple other pages that use it. Also, the MasterPage contains a UserControl defined by me. How can I use/reference that UserControl from a page that uses the MasterPage?

 Many thanks in advance.

Hi Skipy,

You can use FindControl from your child page to reference controls in the master. Here's an example:

Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load

        Dim thisLabel As New Label

        thisLabel = Me.Master.FindControl("lblPageHeading")

        If IsNothing(thisLabel) = False Then
            thisLabel.Text = "About Us"
        End If

    End Sub

 The problem is I'm not trying to reference/ use a Label or any other standard control, but a User Control I made (let's call it UC).

And I cannot do something like:

Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load

        Dim thisUC As New UC

        thisUC = Me.Master.FindControl("myUC")

        If IsNothing(thisUC) = False Then
            thisUC.StartMyVeryOwnMethod(47)
        End If

    End Sub

 ...simply because it does not see UC as a valid class.

In your content page add the following to the top, underneath the Page directive:

<%@ Reference Control="~/MyUserControl.ascx" %>

The content page will then know what the class is.