Determine which UpdatePanel causes the partial (asynchronous) PostBack?

Question

In a page contains two UpdatePanels, How can I know which UpdatePanel causes the partial PostBack ?

I mean in the Page_L

Answer 1

is possible to determine the object inside an update panel an execute the code needed

If (ScriptManager.GetCurrent(Page).IsInAsyncPostBack) Then
                Dim id As String = ScriptManager.GetCurrent(Page).AsyncPostBackSourceElementID
                Dim Obj = UpdatePanel1.FindControlRecursive(id)
                If Not IsNothing(Obj) Then
                    a = 1
                End If
End If

below the function used to find de object inside the update panel. Is an extension of System.Web.UI.Control

a=1 Is the desired code.

 Public Module thisExtensions
         _
        Public Function FindControlRecursive(control As System.Web.UI.Control, id As String) As System.Web.UI.Control
            If control Is Nothing Then
                Return Nothing
            End If
            'try to find the control at the current level
            Dim ctrl As Control = control.FindControl(id)

            If ctrl Is Nothing Then
                'search the children
                For Each child As Control In control.Controls
                    ctrl = FindControlRecursive(child, id)

                    If ctrl IsNot Nothing Then
                        Exit For
                    End If
                Next
            End If
            Return ctrl
        End Function
    End Module