AJAX AutoCompleteExtender: Pass Additional Parameter using ContextKey

<cc1:AutoCompleteExtender ServiceMethod="SearchCustomers" MinimumPrefixLength="2"

        CompletionInterval="100" EnableCaching="false" CompletionSetCount="10" TargetControlID="txtContactsSearch"

        UseContextKey="true" ID="AutoCompleteExtender1" runat="server" FirstRowSelected="false">

    </cc1:AutoCompleteExtender>

<asp:TextBox ID="txtContactsSearch" runat="server" onkeyup = "SetContextKey()"></asp:TextBox>

javascript

<script type="text/javascript">

function SetContextKey()  {

      $find('AutoCompleteExtender1').set_contextKey($get("<%=ddlCountries.ClientID%>").value);

}

</script>

c#

[System.Web.Script.Services. ScriptMethod ()]

[System.Web.Services. WebMethod]

public static List<string> SearchCustomers(string prefixText, int count, string contextKey)

{

        //do something

}

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