Getting error while using session value in cshtml file

Hello.

I want to use session value in cshtml file so I am doing this.

var msg = HttpContext.Session.GetString("resultattrflag");

Also in header I have added this two lines

@using Microsoft.AspNetCore.Http;
@inject IHttpContextAccessor HttpContextAccessor

But still I am getting error like An object reference is required for non-static filed, method or property 'HttpContext.Session'

Can any one help me..Please

Thanks