Ciao a tutti,
ho una semplice applicazione fatta cosi

codice:
<%@ Page Language="VB" AutoEventWireup="true" CodeFile="Default2.aspx.vb" Inherits="Default2" %>


<!DOCTYPE html>

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<meta http-equiv="Content-Type" content="text/html; charset=utf-8"/>
    <title></title>
</head>
<body>
    <form id="form1" runat="server">
    <asp:ScriptManager ID="ScriptManager1" runat="server"></asp:ScriptManager>
    <div>
    
        <asp:TextBox ID="TextBox1" runat="server" ClientIDMode="Static"></asp:TextBox>
        <ajaxToolkit:FilteredTextBoxExtender ID="TextBox1_FilteredTextBoxExtender" runat="server" FilterType="Numbers" TargetControlID="TextBox1" ClientIDMode="Static">
        </ajaxToolkit:FilteredTextBoxExtender>
    
    </div>
    </form>
</body>
</html>
e nel webconfig

codice:
<controls>
        <add assembly="Microsoft.AspNet.Web.Optimization.WebForms" namespace="Microsoft.AspNet.Web.Optimization.WebForms" tagPrefix="webopt" />
        <add tagPrefix="ajaxToolkit" assembly="AjaxControlToolkit" namespace="AjaxControlToolkit" />
      </controls>
Ma non funziona il filtro sulla textbox.

Sto usando il framnework 4.5