限制字数的正则表达式实例

<asp:TextBox runat="server" />
<asp:RequiredFieldValidator runat="server" />
<asp:RegularExpressionValidator runat="server" />
<asp:validationSummary ShowSummary="false" ShowMessageBox="true" HeaderText="错误：" runat="server" />
<asp:Button runat="server" />