Unable to get the ID of the selected item in an autocomplete textbox

Hi,

I am using the following code to populate textbox2 with the selection from textbox1. Is there a way that I can just populate it with the row/record ID? The code below just copies the text from textbox1 to textbox2.

<script language="javascript" type="text/javascript">
      function getSelected(source, eventArgs) {
          document.getElementById('<%=TextBox2.ClientID %>').value = eventArgs.get_value();
      }</script>

cmd.CommandText = "SELECT NPI, [Entity Type Code], [Provider Last Name (Legal Name)], [Provider First Name], [Provider Business Mailing Address City Name], [Provider Business Mailing Address State Name], [Provider Business Mailing Address Postal Code] FROM NPIData WHERE     ([Provider Business Mailing Address State Name] = @State) AND ([Provider Last Name (Legal Name)] LIKE N'%' + @Provider + N'%') ORDER BY [Provider First Name]"
            cmd.Parameters.AddWithValue("@Provider", prefixText)
            cmd.Parameters.AddWithValue("@State", contextKey)
            Dim customers As List(Of String) = New List(Of String)
            Dim reader As SqlDataReader = cmd.ExecuteReader()


            While reader.Read
                customers.Add(reader("Provider Last Name (Legal Name)").ToString + ", " + reader("Provider First Name").ToString + "          " + reader("Provider Business Mailing Address City Name").ToString + ", " + reader("Provider Business Mailing Address State Name").ToString + "  " + reader("Provider Business Mailing Address Postal Code").ToString)


                'Dim entry As String
                'String to Add'
                ' Dim entry = String.Format("{0,24} | {1,24} | {2,24} | {3,24} | {4, 24}", reader("Provider Last Name (Legal Name)").ToString(), reader("Provider First Name").ToString(), reader("Provider Business Mailing Address City Name").ToString(), reader("Provider Business Mailing Address State Name").ToString(), reader("Provider Business Mailing Address Postal Code").ToString())
                'Add the entry'
                'customers.Add(entry)

            End While


            Con.Close()