最近研究Ajax，突然想起有些网站有局部刷新的登陆效果，而Ajax提供了ModalPopup，刚好有类似效果。 因为登陆要调用后台cs页面中的部分功能，所以，结合UpdatePanel实现了这一功能。不知道谁还有更好的实现方式，欢迎共享。 我的源码：SupLogin.rar

Aspx页面主要代码：

 1    <!-- the update controls -->
 2    <asp:UpdatePanel ID="UpdatePanel1" runat="server">
 3        <ContentTemplate>
 4            Welcome back:
 5            <asp:Label runat="server" ID="lbWelcome" Text="Label" CssClass="RedAlert"></asp:Label>
 6        </ContentTemplate>
 7        <Triggers>
 8            <asp:AsyncPostBackTrigger ControlID="btnOK" EventName="Click" />
 9            <asp:AsyncPostBackTrigger ControlID="btnLogout" EventName="Click" />
10        </Triggers>
11    </asp:UpdatePanel>
12    
13    <%-- The login panel--%>
14    <asp:Panel ID="Panel1" runat="server" CssClass="modalPopup" Style="display: none"
15        Width="200px">
16        User:
17        <asp:TextBox ID="txtAlias" runat="server" BackColor="transparent" Text="Jack"></asp:TextBox><br />
18        Pwd:
19        <asp:TextBox ID="TextBox1" runat="server" BackColor="transparent"></asp:TextBox><br />
20        <hr />
21        <asp:Button ID="btnOK" runat="server" Text="OK" Width="80px" OnClick="btnOK_Click" ValidationGroup="Login" />&nbsp;
22        <asp:Button ID="btnCancel" runat="server" Text="Cancel" Width="80px" CausesValidation="False" />
23    </asp:Panel>
24    <br />
25    
26    <%--login and logout panel--%>
27    <asp:Button ID="btnLogin" runat="server" Text="login" /><asp:Button ID="btnLogout"
28        runat="server" Text="Logout" OnClick="btnLogout_Click" />
29        
30    <AjaxControl:ModalPopupExtender ID="ModalPopupExtender1" runat="server" 
31        TargetControlID="btnLogin"
32        PopupControlID="Panel1" 
33        CancelControlID="btnCancel"
34        BackgroundCssClass="modalBackground">
35    </AjaxControl:ModalPopupExtender>

 1 protected void Page_Load(object sender, EventArgs e)
 2    {
 3        lbWelcome.Text = UserName;
 4    }
 5    protected void btnOK_Click(object sender, EventArgs e)
 6    {
 7        this.UserName = txtAlias.Text;
 8        lbWelcome.Text = this.UserName;
 9        this.ModalPopupExtender1.Hide();
10    }
11    private string UserName
12    {
13        get
14        {
15            if (Session["ModalPopup_Users"] == null || string.IsNullOrEmpty(Session["ModalPopup_Users"].ToString()))
16                return "Anonymous";
17            else
18                return Session["ModalPopup_Users"].ToString();
19        }
20        set
21        {
22            Session["ModalPopup_Users"] = value;
23        }
24    }
25    protected void btnLogout_Click(object sender, EventArgs e)
26    {
27        UserName = "Anonymous";
28        lbWelcome.Text = this.UserName;
29    }