前台跨站点获取session

var sessionId = System.Web.HttpContext.Current.Response.Cookies[System.Web.Security.FormsAuthentication.FormsCookieName].Value;
request.SessionId = sessionId;
var ticket = FormsAuthentication.Decrypt(request.SessionId);

//获取

string session = HttpContext.Current.Request.Cookies[FormsAuthentication.FormsCookieName].Value;
var ticket = FormsAuthentication.Decrypt(session);
if (!ticket.Expired)
{
return Convert.ToInt32(ticket.Name);
}

/////////////////////////

/// <summary>
/// 登陆完成
/// </summary>
/// <param name="userId"></param>
/// <param name="isPersistent"></param>
/// <param name="timeoutInMinutes"></param>
/// <returns>表单认证的会话Id</returns>
public string OnLogin(int userId, bool isPersistent, int timeoutInMinutes = 5)
{
//get new ticket
FormsAuthenticationTicket ticket = new FormsAuthenticationTicket(userId.ToString(), isPersistent, timeoutInMinutes);
var session = FormsAuthentication.Encrypt(ticket);

//store in response cookies
HttpCookie cookie = FormsAuthentication.GetAuthCookie(userId.ToString(), isPersistent);
cookie.Value = session;
//cookie.Domain = ".play7th.com";
cookie.Domain = ConfigurationManager.AppSettings["domain"];

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

//store authorization and authentication information to httpcontext and thread context.
HttpContext.Current.Request.Cookies[FormsAuthentication.FormsCookieName].Value = cookie.Value;
var user = GetUserInfoById(userId);
HttpContext.Current.User = new GenericPrincipal(new GenericIdentity(userId.ToString()), user.Roles);
return session;
}