动态加载用户控件 其中的验证控件没有工作

Question

User.Master.us:
//用户登录前后显示不同的控件
protected void Page_Load(object sender, EventArgs e)
    {
      if (Request.Cookies["UserID"] == null)
      {
        //用户未登录
        Control userControl = new Control();
        userControl = LoadControl("~/UserControls/UserLogin.ascx");
        UserPanel.Controls.Add(userControl);
      }
      else
      {
        Control userControl = new Control();
        userControl = LoadControl("~/UserControls/UserInfo.ascx");
        UserPanel.Controls.Add(userControl);
      }
    }UserLogin.ascx:
<%@ Control Language="C#" AutoEventWireup="true" CodeFile="UserLogin.ascx.cs" Inherits="UserControls_UserLogin" %>
<table border="0" cellpadding="1" cellspacing="0" style="border-collapse: collapse">
  <tr>
    <td>
      <asp:Label ID="UserNameLabel" runat="server" AssociatedControlID="UserName">User Name:</asp:Label>                
      <asp:TextBox ID="UserName" MaxLength="20" runat="server" ValidationGroup="LoginGroup"></asp:TextBox>
    </td>                   
    
    <td>
      <asp:Label ID="PasswordLabel" runat="server" AssociatedControlID="Password">Password:</asp:Label>
      <asp:TextBox ID="Password" runat="server" MaxLength="20" TextMode="Password" ValidationGroup="LoginGroup"></asp:TextBox>
    </td>
    
    <td>
      <asp:Label ID="VerifyCodeLabel" runat="server" AssociatedControlID="VerifyCode">VerifyCode:</asp:Label>
    </td>
    <td style="width: 414px">
      <asp:TextBox ID="VerifyCode" runat="server" MaxLength="4" ToolTip="input the number in the picture right please." ValidationGroup="LoginGroup"></asp:TextBox>
      <asp:RequiredFieldValidator ID="VerifycodeRequired" runat="server" SetFocusOnError="True" ControlToValidate="VerifyCode"
      Display="Dynamic" ValidationGroup="LoginGroup">Please input the number in the picture right.</asp:RequiredFieldValidator>  
      <img id="imageCode" src="VerifyCode.aspx?flag=2" alt="please reflash the page." />
    </td>
    
    <td align="center">
      <asp:Button ID="LoginButton" runat="server" CommandName="Login" Text="Sign in" OnClick="LoginButton_Click"/>
    </td>               
  </tr>
  
  <tr>
    <td colspan="4" align="center">
      <a href="Register.aspx">Sign up for free!</a>|<a href="ResetPwd.aspx">Forgotten my password?</a>
      <asp:RequiredFieldValidator ID="UserNameRequired" runat="server" ControlToValidate="UserName" Display="Dynamic" ErrorMessage="Username requires" ValidationGroup="LoginGroup"></asp:RequiredFieldValidator>
      <asp:RegularExpressionValidator ID="REV_UserName" runat="server" ErrorMessage="UserName format illegal." 
      ControlToValidate="UserName" Display="Dynamic" ValidationExpression="^[0-9a-zA-Z]{6,20}$" SetFocusOnError="True" ValidationGroup="LoginGroup"></asp:RegularExpressionValidator>
      <asp:RequiredFieldValidator ID="PasswordRequired" runat="server" ControlToValidate="Password"
      ErrorMessage="Password requires" Display="Dynamic" ValidationGroup="LoginGroup"></asp:RequiredFieldValidator>
      <asp:RegularExpressionValidator ID="REV_Password" runat="server" ControlToValidate="Password"
      Display="Dynamic" ErrorMessage="Password format illegl." ValidationExpression="^[0-9a-zA-Z]{6,20}$" SetFocusOnError="True" ValidationGroup="LoginGroup"></asp:RegularExpressionValidator>
      <asp:Label ID="LabPrompt" runat="server"/>
     </td>
  </tr>
</table> 调试的时候,发现验证控件都失效,即不为空验证和格式验证都没有工作,点击登录按钮后,就到LoginButton_Click事件了
如何实现触发客户端验证?
还是说在这种情况下必须用服务器端验证.期待回复.

Answer 1

<asp:Button ID="LoginButton" runat="server" CommandName="Login" Text="Sign in" OnClick="LoginButton_Click"/> 这里需要加一个验证组：<asp:Button ID="LoginButton" runat="server" CommandName="Login" Text="Sign in" OnClick="LoginButton_Click" ValidationGroup＝"LoginGroup"/>