前台页面：
<body><form id="Form1" 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><br /><input type="checkbox" runat="server" value="记住密码" id="chkRemember" οnclick="CheckRemember()" />记住密码<input type="checkbox" runat="server" value="自动登录" id="chkLogin" οnclick="CheckLogin()" />自动登录<br /><asp:Button runat="server" ID="btnLogin" οnclick="btnLogin_Click" Text="登录" /><input type="button" id="btnClear" οnclick="Clear()" value="取消"/></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></body>
后台页面：
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cookiesHttpCookie 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cookiesHttpCookie 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cookiesloginNameCookie.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>");}}
以上的注释只是我个人的一些思路和理解，如有不正确之处，还望大牛指导指导啊。如觉得文章对你有帮助，请多多支持，你们的支持将会是我写博客的动力。
