. Ashx capture session

I call system. Web. httpcontext. Current. Session in the class library. It is a null value. Is there a way to get this value?
But I can get it in another class library. Both classes are non-page classes, and the session must be non-empty. "Someone asked this question online, I encountered it later in programming.
1: Custom HTTP ProcessingProgram, Inherited from ihttphandler, In the write system. web. httpcontext. current. session ["value"], no problem, but when I want to write this session to a variable, I find that the session value is null, and then query msdn, see "Implementing the irequiressessionstate interface in the Custom HTTP handler to determine whether the handler needs to have read and write access to the session state value". After adding this interface to the custom class

 

2. Capture the session in. ashx and add the irequiressessionstate interface.Remember in handler. ashx
Using system. Web. sessionstate;
Irequiressessionstate