Asp.net Ajax 服务器控件使用--9.FilteredTextBoxExtender

<ajaxToolkit:FilteredTextBoxExtender
       ID="FilteredTextBoxExtender1"
       runat="server"
       TargetControlID="TextBox1"
       FilterType="Numbers" />
      
    <ajaxToolkit:FilteredTextBoxExtender
        ID="FilteredTextBoxExtender2"
        runat="server" 
        TargetControlID="TextBox2"
        FilterType="LowercaseLetters" />   
             
    <ajaxToolkit:FilteredTextBoxExtender
        ID="FilteredTextBoxExtender3"
        runat="server" 
        TargetControlID="TextBox3"
        FilterType="Custom, Numbers"
        ValidChars="+-=/*()." />