<form id="form1" runat="server" method="post" >
<div>
<div>
<asp:Label ID="lbluser" runat="server" Text="用户名"></asp:Label>
<asp:TextBox ID="txtuser" runat="server"></asp:TextBox>
</div>
<div></div>
<div>
<asp:Label ID="lblpwd" runat="server" Text="密　码"></asp:Label>
<asp:TextBox ID="txtpwd" runat="server"></asp:TextBox>
</div>
<div>
<asp:Button ID="Button1" runat="server" Text="登录" OnClick="Button1_Click" style="width: 40px" />
</div>
</div>
</form>

PRotected void Button1_Click(object sender, Eventargs e)
{
string user = Request.Form.Get("txtuser").ToString();//客户端发给服务器需要提交的用户名
string pwd = Request.Form.Get("txtpwd").ToString(); //客户端发给服务器需要提交的密码
if (user == "1" && pwd == "1")
{
Response.Redirect("main.aspx&#63;user=" + user); //跳转到主页面
}
else
{
Response.Write("登录失败");
}

protected void Page_Load(object sender, EventArgs e)
{
string user = Request.QueryString["user"].ToString();//获取user用户名
Response.Write("欢迎" + user + "登录");
}