Public Shared Function GetPostBackControl(ByVal page As Page) As Control
        Dim control As Control = Nothing

        Dim ctrlname As String = page.Request.Params.[Get]("__EVENTTARGET")
        If ctrlname IsNot Nothing AndAlso ctrlname <> String.Empty Then
            control = page.FindControl(ctrlname)
        Else
            For Each ctl As String In page.Request.Form
                Dim c As Control = page.FindControl(ctl)
                If TypeOf c Is System.Web.UI.WebControls.Button Then
                    control = c
                    Exit For
                End If
            Next
        End If
        Return control
    End Function

Many thanks to Ryan Farley (http://www.ryanfarley.com/blog/archive/2005/03/11/1886.aspx) for this code. I converted the C# to VB for my own project.  Saved my sanity it did!