Session is null in Generic Handler (ashx)

System.NullReferenceException (“Object reference not set to an instance of an object”) is thrown when you try to read/write the Session object in a generic handler without implementing System.Web.SessionState.IRequiresSessionState.

If your intention is to read only, then use IReadOnlySessionState instead.


<%@ WebHandler Language="C#" Class="MyHandler" %>

using System;
using System.Web;

public class MyHandler : IHttpHandler, System.Web.SessionState.IRequiresSessionState
    public void ProcessRequest (HttpContext context) {
        context.Response.ContentType = "text/plain";
        context.Response.Write("Hello World");
    public bool IsReusable {
        get {
            return false;



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