这个东西太纠结了~贴出来代码，供大家享用
分三个部分：.config .aspx .aspx.cs
//web.config
<appSettings>
<add key="keystring" value="Data Source=ZRQ-PC;Initial Catalog=OnlineJudge;Integrated Security=True"/>
</appSettings>
//page.aspx
<form id="form2" name="form2" method="post" action="">
<asp:Panel ID="unlogin" runat="server">
<div class="Login" align="center">
<p>Login</p>
用户名<asp:TextBox ID="username" runat="server" Width="106px"></asp:TextBox><br />
密码 <asp:TextBox ID="password" runat="server" Height="22px" Width="106px"></asp:TextBox><br />
<asp:Button ID="submit" runat="server" Text="登录" onclick="submit_Click" />
<asp:Button ID="register" runat="server" Text="注册" />
</div>
</asp:Panel>
<asp:Panel ID="allogin" runat="server" Visible="false">
<div class="Login" align="center">
<asp:Label ID="welcome" runat="server" Text="Label"></asp:Label><br />
<asp:Button ID="alterinfo" runat="server" Text="修改信息" /><br />
<asp:Button ID="logout" runat="server" Text="注销登陆" /><br />
<asp:Button ID="register1" runat="server" Text="注册新用户" /><br />
<asp:Button ID="relogin" runat="server" Text="重新输入密码" />
</div>
</asp:Panel>
</form>
//page.a
