Hi! I'm trying to make a button for download a file, but I'm a little in trouble :(

Which is the correct pattern with Razor developing model?

In v5.3 WebForms setting the IsUpload property to the Click event was enough.
isUpload doesn't exist anymore, so i've tried to use CustomConfig (look the commented row), but it doesn't work.

@page "{handler?}"
@model ExtCookbook.Pages.FileDownloadModel
    ViewData["Title"] = "File Download";

<ext-section target="Main">
    <ext-panel id="MainContainer" region="Center" layout="Border" scrollable="true" paddingAsString="0">
            <ext-button model="@Model.myButton" />
using Ext.Net;
using Ext.Net.Core;
using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.Mvc.RazorPages;

namespace ExtCookbook.Pages
    public class FileDownloadModel : PageModel
        public Button myButton { get; set; }

        public void OnGet()
            var btn = new Button() { Id = "DownloadButton", IconCls = "x-md md-icon-get-app", Text = "Download" };
            btn.DirectEvents.Click.Method = HttpMethod.POST;
            btn.DirectEvents.Click.Url = $"?handler=DownloadButtonClick";
            //btn.DirectEvents.Click.CustomConfig = new JsObject() { { "isUpload", true } };

            myButton = btn;

        public IActionResult OnPostDownloadButtonClick(JsObject jObj)
            return File(System.Text.Encoding.UTF8.GetBytes("I have been downloaded via a DirectEvent!"), "text/plain", "test.txt");
Any suggestion is much appreciated!
Thank you very much.