C# 如何知道会话是否已设置

How to know if a session has been set

提问by Misters

In php i used to use

在 php 中我曾经使用

session_start();
if(isset(SESSION["user"]))
{
   //session is set
}
els{
    // there is no session 
}

but do i do that in asp.net? I mean. What code can tells wheather a session is set or not

但我在asp.net 中这样做吗？我的意思是。什么代码可以告诉是否设置了会话

ex: asp.net c#

例如：asp.net c#

//login.aspx
SESSION["USER"];

//user_profile.aspx
if(SESSION["USER"])// how do i validate that??
{

}

采纳答案by jTC

SESSION["USER"]; //this should throw an error since it's not setting a value and not a method.

You can test your session values like this:

您可以像这样测试会话值：

if (Session["USER"] != null)
{
    //do something interesting
}

回答by Abe Miessler

If you want to check for the existance of a session variable this will be fine:

如果您想检查会话变量是否存在，这很好：

if(Session["USER"] != null)
{
    //If you get here a session variable "USER" exists...
}

Though it is possible to disable session statein an asp.net application it is very rare to see that.

尽管可以在 asp.net 应用程序中禁用会话状态，但这种情况很少见。

回答by Soner G?nül

From php side, cince issetfunction

从 php 端，cince isset函数

Determine if a variable is set and is not NULL.

确定变量是否已设置且不为 NULL。

Just check if this session nullor not like:

只需检查此会话是否null喜欢：

if(Session["USER"] != null)
{
  // Do something
}