string strname = HttpContext.Current.User.Identity.Name;//获取到带域名的用户string name = HttpContext.Current.User.Identity.Name.Substring(HttpContext.Current.User.Identity.Name.IndexOf("\\") + 1, HttpContext.Current.User.Identity.Name.Length - HttpContext.Current.User.Identity.Name.IndexOf("\\") - 1);

<form runat="server">
<input type="hidden" id="hidPass" runat="server" />
<input type="text" runat="server" id="txtLoginName" />
<asp:TextBox runat="server" ID="txtPassWord" class="textwidthheigh" TextMode="Password"></asp:TextBox>
<input type="checkbox" runat="server" value="记住密码" id="chkRemember" onclick="CheckRemember()" />
<input type="checkbox" runat="server" value="自动登录" id="chkLogin" onclick="CheckLogin()" />
<asp:Button runat="server"  id="btnLogin"  onclick="btnLogin_Click"  />
<input type="button" id="btnClear" onclick="Clear()"  />
</form><script type="text/javascript" language="javascript">
//页面加载用户名输入框获得焦点        document.getElementById("txtLoginName").focus();function Clear() {
//用户点击取消，清空用户名和用户密码            document.getElementById("txtLoginName").value = "";document.getElementById("txtPassWord").value = "";}function CheckLogin() {//用户勾选自动登录时，把记住密码也勾选上var remember = document.getElementById("chkRemember");remember.checked = true;}function CheckRemember() {var remenber = document.getElementById("chkRemember");var login = document.getElementById("chkLogin");if (remenber.checked == false) {login.checked = false;//用户去掉记住密码时，也把自动登录去掉            }}</script>

protected void Page_Load(object sender, EventArgs e){ if (!IsPostBack){　　　　　　　　　//获取客户端的Cookies，分别两个cookies，一个登陆名，一个密码                HttpCookie LoginNameCookie = Request.Cookies["Bic_LoginName"];HttpCookie LoginPassCookie = Request.Cookies["Bic_Pass"];if (LoginNameCookie != null){//登录名的cookies不为空，填充登陆名                    txtLoginName.Value = LoginNameCookie.Value;}if (LoginPassCookie != null){//密码cookies不为空，给密码框和隐藏密码框填充，当然我们的密码是加密过才存到cookies去的，至于以藏文本框的作用后面就会看到this.txtPassWord.Attributes.Add("value",LoginPassCookie.Value+"");hidPass.Value = LoginPassCookie.Value + "";//赋值给隐藏控件chkRemember.Checked = true;}//获取是否有勾选自动登录的cookies                HttpCookie Login = Request.Cookies["Bic_LoginAuto"];//当用户在系统点击退出时if (Request["opFlag"] == "Exit"){this.txtPassWord.Attributes.Add("value", "");//把密码去掉chkRemember.Checked = false;//记住密码去掉HttpCookie loginNameCookie = Request.Cookies["Bic_LoginName"];//获取登录名cookies                    HttpCookie loginPassCookie = Request.Cookies["Bic_Pass"];//获取密码cookiesif (loginNameCookie != null){//把cookies时间设为-2相当于删掉了cookies                        loginNameCookie.Expires = DateTime.Now.AddDays(-2);Response.Cookies.Set(loginNameCookie);}if (loginPassCookie != null){//把密码的cookies也删掉                        loginPassCookie.Expires = DateTime.Now.AddDays(-2);Response.Cookies.Set(loginPassCookie);}//自动登录cookies也一样                    HttpCookie login = Request.Cookies["Bic_LoginAuto"];if (login != null){login.Expires = DateTime.Now.AddDays(-2);Response.Cookies.Set(login);}}else//用户打开登录界面时                {//自动登录cookies不为空，用户名不为空，隐藏框密码不为空if (Login != null && txtLoginName.Value != "" && hidPass.Value != ""){SysUser user = new SysUser();user.Login_Name = txtLoginName.Value;user.Login_Pass = hidPass.Value;int i = SysUserBLL.Login(user);//验证登录if (i > 0){//成功登录跳转到default.aspx页面                            Page.Session["Login_Name"] = user.Login_Name;HttpContext.Current.Session["Display_Name"] = SysUserBLL.getDisplayNameByname(user.Login_Name);Response.Write("<script>window.location='Default.aspx';</script>");Response.End();}}}}}//点击登录按钮事件protected void btnLogin_Click(object sender, EventArgs e)        {　　　　　　　//判断是否为空            if (txtLoginName.Value.Trim() != "" && txtPassWord.Text.Trim() != "")            {                SysUser user = new SysUser();                user.Login_Name = txtLoginName.Value.Trim();                user.Login_Pass = CommonHelper.MD5encipher(txtPassWord.Text.Trim());//MD5加密                HttpCookie LoginNameCookie = Request.Cookies["Bic_LoginName"];                HttpCookie LoginPassCookie = Request.Cookies["Bic_Pass"];                if (LoginNameCookie != null)//如果是记住密码情况                {                    if (txtLoginName.Value.Trim() == LoginNameCookie.Value.Trim())//读取到cookies保存的用户名和文本框用户名相同，预防用户又改动                    {                        if (LoginPassCookie != null)                        {                            if (txtPassWord.Text.Trim() == LoginPassCookie.Value.Trim())//cookies读取到的密码和文本框密码相同                            {                                user.Login_Pass = txtPassWord.Text.Trim();                            }

                        }                    }                }                int i = SysUserBLL.Login(user);//验证登录                if (i > 0)                {                    if (chkRemember.Checked == true)//记住密码                    {                        HttpCookie loginNameCookie = new HttpCookie("Bic_LoginName", user.Login_Name);                        HttpCookie loginPassCookie = new HttpCookie("Bic_Pass", user.Login_Pass);                        loginPassCookie.Expires = DateTime.Now.AddDays(1);                        loginNameCookie.Expires = DateTime.Now.AddDays(1);                        Response.Cookies.Add(loginNameCookie);                        Response.Cookies.Add(loginPassCookie);                        if (chkLogin.Checked == true)//自动登录                         {                            HttpCookie Login = new HttpCookie("Bic_LoginAuto", "true");                            Login.Expires = DateTime.Now.AddDays(1);                            Response.Cookies.Add(Login);                        }                        else                        {                            HttpCookie Login = Request.Cookies["Bic_LoginAuto"];                            if (Login != null)                            {                                Login.Expires = DateTime.Now.AddDays(-2);                                Response.Cookies.Set(Login);                            }                        }                    }                    else//没选记住密码                    {                        HttpCookie loginNameCookie = Request.Cookies["Bic_LoginName"];                        HttpCookie loginPassCookie = Request.Cookies["Bic_Pass"];                        if (loginNameCookie != null)                        {                            loginNameCookie.Expires = DateTime.Now.AddDays(-2);                            Response.Cookies.Set(loginNameCookie);                        }                        if (loginPassCookie != null)                        {                            loginPassCookie.Expires = DateTime.Now.AddDays(-2);                            Response.Cookies.Set(loginPassCookie);                        }                    }                    Page.Session["Login_Name"] = user.Login_Name;                    HttpContext.Current.Session["Display_Name"] = SysUserBLL.getDisplayNameByname(user.Login_Name);                    Response.Write("<script>window.location='Default.aspx';</script>");                }                else                {                    Response.Write("<script>alert('用户名或密码错误!');window.location='Login.aspx';</script>");                }            }            else            {                Response.Write("<script>alert('请输入账号和密码!');window.location='Login.aspx';</script>");            }        }