Pass user Control In Shared Functions

Dear Friends I am working on a code where I am trying to pass value from Javascript to serverside
Every things working fine but we are having a global user control that we use to display alert
When I am trying to pass that user control into shared functions its not working can some one give some quick idea on it

Code:

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  <uc_alert:alert runat="server" ID="ucalert"  />

<System.Web.Services.WebMethod()> _
    Public Shared Sub GetContactName(ByVal error_message As String)
        _global.alert_message_show(ucalert, "error", error_message, -1)

    End Sub

Public Class _global

    Shared Sub alert_message_show(uc_alert As UserControl, alert_type As String, message_text As String, alert_duration As Integer)
End Sub
End Class

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Can we have a quick idea how to pass usercontrol ucalert into shared functions

Thanks