The AutoCompleteExtender control provides you the ability to help the end user find what they might
be looking for when they have to type in search terms within a text box. Like the product Google Suggest
once you start typing characters in the text box, you will get results from a
datastore that matches what you have typed so far.
To establish something similar for yourself, create a new page that contains only a ScriptManager control,
an AutoCompleteExtender control, and a TextBox control. The ASP.NET portion of the page should
appear as presented in :
<br />
<br />
lt;%@ Page Language="C#" AutoEventWireup="true" CodeFile="AutoComplete.aspx.cs"
Inherits="AutoComplete" %>
<%@ Register Assembly="AjaxControlToolkit" Namespace="AjaxControlToolkit"
TagPrefix="cc1" %>
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title>AutoComplete</title>
</head>
<body>
<form id="form1" runat="server">
<div>
<asp:ScriptManager ID="ScriptManager1" runat="server">
</asp:ScriptManager>
<cc1:AutoCompleteExtender ID="AutoCompleteExtender1" runat="server"
TargetControlID="TextBox1" ServiceMethod="GetCompletionList"
UseContextKey="True">
</cc1:AutoCompleteExtender>
<asp:TextBox ID="TextBox1" runat="server"></asp:TextBox>
</div>
</form>
</body>
</html>
Again, like the other ASP.NET AJAX controls, you extend the TextBox control using the TargetControlID
property. When you first add these controls to the page, you will not have the ServiceMethod
property defined in the AutoCompleteExtender control. Using Visual Studio 2008, you can make the
framework for a service method and tie the extender control to this method all from the design surface.
After expanding the TextBox control’s smart tag, select the Add AutoComplete page method option from
the provided menu.
This action creates a service method in the code-behind for your page.
using System.Collections.Generic;
using System.Data;
using System.Data.SqlClient;
public partial class AutoComplete : System.Web.UI.Page
{
[System.Web.Services.WebMethodAttribute(),
System.Web.Script.Services.ScriptMethodAttribute()]
public static string[] GetCompletionList(string prefixText, int count,
string contextKey)
{
SqlConnection conn;
SqlCommand cmd;
string cmdString =
"Select CompanyName from Customers WHERE CompanyName LIKE ’" +
prefixText + "%’";
conn = new
SqlConnection(@"Data Source=.\SQLEXPRESS;
AttachDbFilename=|DataDirectory|\NORTHWND.MDF;
Integrated Security=True;User Instance=True");
cmd = new SqlCommand(cmdString, conn);
conn.Open();
SqlDataReader myReader;
<pre lang="xml">List<string> returnData = new List<string>();
myReader = cmd.ExecuteReader(CommandBehavior.CloseConnection);
while (myReader.Read())
{
returnData.Add(myReader["CompanyName"].ToString());
}
return returnData.ToArray();
}
}
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