Visual Studio ASP.Net expand and collapse issue in ashx generic handlers

You can force Visual Studio to ignore the fact that it's code in front you're working with by going to:

Tools | Options

And opening the "Text Editor | File Extensions" tab.

Create a new entry for extension "ashx", mapped to editor "Microsoft Visual C#" (or "Microsoft Visual Basic", as your preference takes you), and "Add" it.

OK the dialog, close and re-open your ashx file, and your code blocks willl collapse to your hearts content, but the @ directive will be rather ugly.

You have the same issue if you have serverside script in the .aspx file (for example in a web site project and you don't "Place code in a seperate file"), then you cannot collapse the class blocks in there either.

Create a class in the App_Code directory, which the ashx-file just references... like this:

SomethingHandler.ashx:

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

And in the App_Code folder I've created the file SomethingHandler.cs with class SomethingHandler

using System;
using System.Web;
// using blabla...

public class SomethingHandler : IHttpHandler
{
        public void ProcessRequest(HttpContext c)
        {
    etc...

Now I can just open SomethingHandler.cs, edit my C# code with #region collapsing, because the .cs file is opened in the right editor :)

@ WebHandler docs

Tested in VS 2019.