点击“登录”时保存Cookie,如下
HttpCookie cookie = new HttpCookie("UserName");
cookie.Value = Session["admin"].ToString();
Response.Cookies.Add(cookie);
cookie.Expires = System.DateTime.Now.AddDays(7);//设置过期时间是7天

在“登录”页里面如下：
protected void Page_Load(object sender, EventArgs e)
  {
  if (Request.Cookies["UserName"] != null)
  {
  Response.Redirect(Url);
  }
  }
 
思路：在前次登录时保存登录信息到Cookie里，下次登录时验证这个登录信息是否存在，存在就直接跳转。

//一些相关信息

ASP.NET中的cookie：创建Cookie方法 (1)

Response.Cookies["userName"].Value = “admin";

Response.Cookies[“userName”].Expires = DateTime.Now.AddDays(1);

//如果不设置失效时间,Cookie信息不会写到用户硬盘,浏览器关闭将会丢弃。

ASP.NET中的cookie：创建Cookie方法 (2)

HttpCookie aCookie = new HttpCookie(“lastVisit”);

//上一次访问时间

aCookie.Value = DateTime.Now.ToString();

aCookie.Expires = DateTime.Now.AddDays(1);

Response.Cookies.Add(aCookie);

ASP.NET中的cookie：访问Cookie方法(1)

 

if(Request.Cookies["userName"] != null)

Label1.Text = Server.HtmlEncode(Request.Cookies["userName"].Value);

 

访问Cookie方法(2)

 

if(Request.Cookies["userName"] != null) {

HttpCookie aCookie = Request.Cookies["userName"];

Label1.Text = Server.HtmlEncode(aCookie.Value);

}

ASP.NET中的cookie：创建多值Cookie方法 (1)

Response.Cookies["userInfo"]["userName"] = “admin";

Response.Cookies["userInfo"]["lastVisit"] = DateTime.Now.ToString();

Response.Cookies["userInfo"].Expires = DateTime.Now.AddDays(1);

ASP.NET中的cookie：创建多值Cookie方法 (2)

HttpCookie aCookie = new HttpCookie("userInfo");

aCookie.Values["userName"] = “admin";

aCookie.Values["lastVisit"] = DateTime.Now.ToString();

aCookie.Expires = DateTime.Now.AddDays(1);

Response.Cookies.Add(aCookie);

 

ASP.NET中的cookie：读取多值Cookie

 

HttpCookie aCookie = Request.Cookies["userInfo"];

string userName=aCookie.Values[“userName”];

string lastVisit=aCookie.Values[“lastVisit”];