如何在ASP.NET中创建持久性Cookie？

我正在使用以下行创建cookie：

HttpCookie userid = new HttpCookie("userid", objUser.id.ToString());
userid.Expires.AddYears(1);
Response.Cookies.Add(userid);

现在如何使其持久化？

如果在关闭浏览器后再次访问同一页面，则无法找回。

这是您可以执行的操作。

编写持久性cookie。

//create a cookie
HttpCookie myCookie = new HttpCookie("myCookie");

//Add key-values in the cookie
myCookie.Values.Add("userid", objUser.id.ToString());

//set cookie expiry date-time. Made it to last for next 12 hours.
myCookie.Expires = DateTime.Now.AddHours(12);

//Most important, write the cookie to client.
Response.Cookies.Add(myCookie);

读取持久性cookie。

//Assuming user comes back after several hours. several < 12.
//Read the cookie from Request.
HttpCookie myCookie = Request.Cookies["myCookie"];
if (myCookie == null)
{
    //No cookie found or cookie expired.
    //Handle the situation here, Redirect the user or simply return;
}

//ok - cookie is found.
//Gracefully check if the cookie has the key-value as expected.
if (!string.IsNullOrEmpty(myCookie.Values["userid"]))
{
    string userId = myCookie.Values["userid"].ToString();
    //Yes userId is found. Mission accomplished.
}

尽管接受的答案是正确的，但并未说明原始代码为何无法正常工作。

您问题中的错误代码：

HttpCookie userid = new HttpCookie("userid", objUser.id.ToString());
userid.Expires.AddYears(1);
Response.Cookies.Add(userid);

看第二行。到期的基础是Expires属性，该属性包含默认值1/1/0001。上面的代码评估为1/1/0002。此外，评估不会保存回属性。而是应使用当前日期的基础设置Expires属性。

更正的代码：

HttpCookie userid = new HttpCookie("userid", objUser.id.ToString());
userid.Expires = DateTime.Now.AddYears(1);
Response.Cookies.Add(userid);

FWIW在将用户名之类的内容存储在未加密的cookie中时要非常小心。这样做会使您的网站很容易出现Cookie中毒的情况，用户可以很容易地冒充其他用户。如果您正在考虑类似的事情，我强烈建议您直接使用表单身份验证cookie。

bool persist = true;

var cookie = FormsAuthentication.GetAuthCookie(loginUser.ContactId, persist);

cookie.Expires = DateTime.Now.AddMonths(3);

var ticket = FormsAuthentication.Decrypt(cookie.Value);

var userData = "store any string values you want inside the ticket
                 extra than user id that will be encrypted"

var newTicket = new FormsAuthenticationTicket(ticket.Version, ticket.Name,
     ticket.IssueDate, ticket.Expiration, ticket.IsPersistent, userData);

cookie.Value = FormsAuthentication.Encrypt(newTicket);

Response.Cookies.Add(cookie);

然后，您可以随时通过以下方式从ASP.NET页中阅读此内容：

string userId = null;
if (this.Context.User.Identity.IsAuthenticated) 
{
    userId = this.Context.User.Identity.Name;
}

据我了解，您使用ASP.NET身份验证并设置cookie持久化，您需要设置FormsAuthenticationTicket.IsPersistent = true这是主要思想。

bool isPersisted = true;
var authTicket = new FormsAuthenticationTicket(
1,
user_name, 
DateTime.Now,
DateTime.Now.AddYears(1),//Expiration (you can set it to 1 year)
isPersisted,//THIS IS THE MAIN FLAG
addition_data);
    HttpCookie authCookie = new HttpCookie(FormsAuthentication.FormsCookieName, authTicket );
    if (isPersisted)
        authCookie.Expires = authTicket.Expiration;

HttpContext.Current.Response.Cookies.Add(authCookie);

您需要将此添加为最后一行...

HttpContext.Current.Response.Cookies.Add(userid);

当您需要读取cookie的值时，可以使用类似于以下的方法：

    string cookieUserID= String.Empty;

    try
    {
        if (HttpContext.Current.Request.Cookies["userid"] != null)
        {
            cookieUserID = HttpContext.Current.Request.Cookies["userid"];
        }
    }
    catch (Exception ex)
    {
       //handle error
    }

    return cookieUserID;

//添加cookie

var panelIdCookie = new HttpCookie("panelIdCookie");
panelIdCookie.Values.Add("panelId", panelId.ToString(CultureInfo.InvariantCulture));
panelIdCookie.Expires = DateTime.Now.AddMonths(2); 
Response.Cookies.Add(panelIdCookie);

//读取Cookie

    var httpCookie = Request.Cookies["panelIdCookie"];
                if (httpCookie != null)
                {
                    panelId = Convert.ToInt32(httpCookie["panelId"]);
                }