FilteredTextBox控件，該控件用於控制用戶的輸入值的范圍。
實例代碼如下所示：
<%...@ Page Language="C#" AutoEventWireup="true" CodeFile="FilteredTextBoxDemo.ASPx.cs"
Inherits="FilteredTextBoxDemo" %>
<%...@ Register Assembly="System.Web.Extensions, Version=1.0.61025.0, Culture=neutral,
PublicKeyToken=31bf3856ad364e35"
Namespace="System.Web.UI" TagPrefix="ASP" %><%...@ Register Assembly="AjaxControlToolkit" Namespace="AJaxControlToolkit" TagPrefix="cc1" %><!DOCTYPE html PUBLIC "-//W3C//DTD XHtml 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xHtml1-transitional.dtd"><html XMLns="http://www.w3.org/1999/xHtml" ><head runat="server"> <title>無標題頁</title></head><body> <form id="form1" runat="server"> <div> <ASP:ScriptManager ID="ScriptManager1" runat="server"> </ASP:ScriptManager> <table border="0"> <tr> <td>只允許輸入數字</td>
<td><ASP:TextBox ID="TextBox1" runat="server" /> </td> </tr> <tr> <td>只允許輸入小寫字母:</td> <td><ASP:TextBox ID="TextBox2" runat="server" /></td> </tr> <tr> <td>只允許輸入 (+,-,*,/,=,.) 和數字:</td> <td> <asp:TextBox ID="TextBox3" runat="server"></ASP:TextBox></td> </tr> </table> <cc1:FilteredTextBoxExtender ID="FilteredTextBoxExtender1" runat="server" TargetControlID="TextBox1" FilterType="Numbers" /> <cc1:FilteredTextBoxExtender ID="FilteredTextBoxExtender2" runat="server" TargetControlID="TextBox2" FilterType="LowercaseLetters" /> <cc1:FilteredTextBoxExtender ID="FilteredTextBoxExtender3" runat="server" TargetControlID="TextBox3" FilterType="Custom, Numbers" ValidChars="+-=/*()." /> </div> </form></body></Html>
