本程序功能是使用Session将用户输入的用户名保存在Session中(登录成功情况下，登录失败不会有Session值)，其它页面想访问时会先判断是否有之前存的Session值。
登录Login.htm页面:
<head> <title></title> <script type="text/javascript"> //刷新验证码 function refreshYZM() { var imgYZM = document.getElementById("imgYZM"); imgYZM.src = "YanZhengMa.ashx?t="+new Date(); } </script> </head> <body> <form action="Login.ashx" method="post"> <table> <tr><td>用户名</td><td><input type="text" name="username" /></td></tr> <tr><td>密码</td><td><input type="password" name="password" /></td></tr> <tr> <td> <img src="YanZhengMa.ashx" id="imgYZM" onclick="refreshYZM()" /> </td><td><input type="text" name="yzm" /> </td> </tr> <tr><td><input type="submit" name="btnLogin" value="登录" /></td><td>@msg</td></tr> </table> </form> </body> </html>
生成验证码YanZhengMa.ashx:
public void ProcessRequest(HttpContext context) { context.Response.ContentType = "image/jpeg"; Random rand = new Random(); int num = rand.Next(1000, 10000);//生成4位随机数 string code = num.ToString(); context.Session[Login.YZM] = code; using (Bitmap bmp = new Bitmap(45, 25)) { using (Graphics g = Graphics.FromImage(bmp)) using (Font font = new Font(FontFamily.GenericSerif, 15)) { g.DrawString(code, font, Brushes.Red, new PointF(0, 0)); } bmp.Save(context.Response.OutputStream, ImageFormat.Jpeg); } }
登录Login.ashx页在(必须实现IRequiresSessionState接口，在using System.Data.SqlClient;命名空间下)：
public const string YZM = "YZM";//存储验证码 public const string LOGINUSERNAME = "LoginUserName";//将登录用户名存到Session，供多个页面访问 public const string LOGINURL = "LoginUrl";//尝试登录的时候的页面地址 public void ProcessRequest(HttpContext context) { context.Response.ContentType = "text/html"; string btnLogin = context.Request["btnLogin"];//获取点击按钮 string html = CommonHelper.ReadHtml("~/Login.htm");//获取Login.htm页面内容 if (string.IsNullOrEmpty(btnLogin))//判断按钮是否点击 { html = html.Replace("@msg", ""); context.Response.Write(html); } else { string yzm = context.Request["yzm"];//获取用户输入的验证码 string yzmInServer = (string)context.Session[YZM];//获取服务器的验证码 if (yzm != yzmInServer)//判断用户输入与服务器的验证码 { html = html.Replace("@msg","<font color=red>验证验错误</font>"); context.Response.Write(html); return; } string username = context.Request["username"]; string password = context.Request["password"]; int r = (int)SQLHelper.ExecuteScalar("select count(*) from Users where name=@name and password=@password", new SqlParameter { ParameterName = "@name", Value = username }, new SqlParameter { ParameterName = "@password", Value = password }); if (r <= 0) { html = html.Replace("@msg", "<font color=red>用户名或密码错误</font>"); context.Response.Write(html); return; } else { //如果登录成功 context.Session[LOGINUSERNAME] = username;//把当前登录的用户名写到Session中 //获取上一次访问网址的Session值,在QueryYuE.ashx和ChangePassword.ashx中已作判断， //当没登录时，就设置Session值"LOGINURL"为要访问的页面 string navUrl = (string)context.Session[LOGINURL]; if (navUrl != null) { context.Response.Redirect(navUrl);//重定向回到上一次访问的页面，动态获取 } else { context.Response.Write("看，美丽的图片。。。。。"); } } } }
修改密码ChangePassword.ashx(须实现IRequiresSessionState)：
public void ProcessRequest(HttpContext context) { string username = (string)context.Session[Login.LOGINUSERNAME];//获取登录时存入的Session值 if (username == null)//如果没登录强制性的访问此页面，则重定向到登陆页面 { context.Session[Login.LOGINURL] = context.Request.Url.ToString();//把当前地址存到Session中 context.Response.Redirect("Login.ashx"); } else { context.Response.Write("修改密码。。。，当前登录用户<a href='Loginout.ashx'>退出登录</a>" + username); } }
余额查询QueryYuE.ashx(须实现IRequiresSessionState):
public void ProcessRequest(HttpContext context) { context.Response.ContentType = "text/html"; string username = (string)context.Session[Login.LOGINUSERNAME]; if (username == null)//如果没登录强制性的访问此页面，则重定向到登陆页面 { context.Session[Login.LOGINURL] = context.Request.Url.ToString();//把当前地址存到Session中 context.Response.Redirect("Login.ashx"); } else { context.Response.Write("查询余额。。。，当前登录用户。<a href='Loginout.ashx'>退出登录</a>" + username); } }
退出登录Loginout.ashx(须实现IRequiresSessionState):
public void ProcessRequest(HttpContext context) { context.Response.ContentType = "text/html"; context.Session.Abandon();//销毁Session context.Response.Redirect("Login.ashx"); }
帮助类CommonHelper.cs:
public class CommonHelper { public static string ReadHtml(string path) { string fillPath = HttpContext.Current.Server.MapPath(path); string html = File.ReadAllText(fillPath); return html; } }