Using AutoComplete Ajax Control With Separate ID Field from Name Field ...

AutoComplete Extender offers a convenient way to select values froma TextBox. One problem is that multiple details can be displayed, but the whole text is selected by default. I wanted to allow multiple AutoCompletes, select the id without the other details and append the appropriate delimeter in between entries. First, I setup the WebService method. Note that the Stock object has Symbol and Name properties:

   [WebMethod]
    public string[] GetStocksInPrefix(string prefixText, int count)
    {
        int curCount = 0;
        if (count == 0)
        {
            count = 10;
        }
        List<string> items = new List<string>();
        JavaScriptSerializer jss = new JavaScriptSerializer();
        string[] stocks = null;
        string connectionString = getConnectionString("ConnectionString");
        SqlDataReader rdr = null;
        SqlConnection conn = new SqlConnection(connectionString);
        System.Data.SqlClient.SqlCommand command = new System.Data.SqlClient.SqlCommand("sproc_aspnet_GetStocksByPrefix", conn);
        try
        {
            command.CommandType = System.Data.CommandType.StoredProcedure;
            conn.Open();
            command.Parameters.AddWithValue("@Prefix", prefixText+"%");
            rdr = command.ExecuteReader();
            string tmp = string.Empty;
            Stock _stock = null;
            while (rdr.Read() && curCount<count )
            {
                _stock = new Stock(rdr["Symbol"].ToString(), rdr["Name"].ToString(), rdr["Exchange"].ToString());
                tmp = rdr["Symbol"] + " " + rdr["Name"];
                items.Add(AutoCompleteExtender.CreateAutoCompleteItem(tmp, jss.Serialize(_stock)));
                curCount++;
            }
            command.Parameters.Clear();
        }
        catch (Exception ex)
        {
        }
        finally
        {
            if (rdr != null) rdr.Close();
            if(conn!=null) conn.Close();
        }
        return items.ToArray();
    }

Then, I add the javascript event, OnSymbolSelected,to the OnClientItemSelected event in the AutoComplete Extender:

                    <asp:TextBox ID="txtSymbols" runat="server" Width="300px"></asp:TextBox>
                    <cc1:AutoCompleteExtender ID="AutoCompleteExtender1" runat="server"
                        TargetControlID="txtSymbols" ServiceMethod="GetStocksInPrefix"
                        ServicePath="~/WebServiceAutoCompleteSymbol.asmx" MinimumPrefixLength="2"
                        CompletionListHighlightedItemCssClass="watermark" CompletionSetCount="10"
                        DelimiterCharacters=", "
                        CompletionListElementID="Symbol"
                        CompletionListItemCssClass="watermarkMatch"                       
                        EnableCaching="true" CompletionInterval="1000" OnClientItemSelected="OnSymbolSelected"
                         >
                    </cc1:AutoCompleteExtender>

Finally, add the javascript function to the aspx page. This function reads the Stock object into results, takes the SelectedText and gets the original string before the new text was completed by replacing the completed text with an empty string. If it is an additional field (that does not contain or ,, then only the id (symbol in this case) is added. Othewise, the original id plus the delimeter and the new id is added:

<script type="text/javascript" language="javascript">  
    function OnSymbolSelected(source, eventArgs)  
    {  
        var results = eval((  + eventArgs.get_value() + ));  
        if (results.symbol != null)   { 
            var symbols = document.getElementById(<%= txtSymbols.ClientID %>).value;
            var original = symbols.replace((results.symbol+ +results.name),);
            if (original.indexOf( )>0 || original.indexOf(,)>0)
                document.getElementById(<%= txtSymbols.ClientID %>).value = original + ( + results.symbol);
            else 
                document.getElementById(<%= txtSymbols.ClientID %>).value = results.symbol;
            }
    }  
</script> 

 Original Source:
http://techron.blogspot.com/2008/12/using-autocomplete-ajax-control-with.html