Asp.net core - How to implement realtime using signalR - ajax

Question

I am adding a comments part in my project, I would like to use real-time using signalR.
I'm using Ajax for adding comments, and I want to refresh data for all users after the comment inserts into the database.
This is my code in Razor view :
<form asp-action="SendComment" asp-controller="Home" asp-route-subId="#Model.Subject.Id"
asp-route-AccountName="#User.Identity.Name" onsubmit="return jQueryAjaxPost(this);">
<textarea name="comment" id="myTextbox" required class="form-control mb-3" rows="3" cols="1" placeholder="اكتب هنا"></textarea>
<div class="d-flex align-items-center">
<button type="submit" id="myBtn" class="btn bg-blue-400 btn-labeled btn-labeled-right ml-auto"><b><i class="icon-paperplane"></i></b> ارسال</button>
</div>
</form>
Ajax code :
jQueryAjaxPost = form => {
try {
$.ajax({
type: 'POST',
url: form.action,
data: new FormData(form),
contentType: false,
processData: false,
success: function (res) {
if (res.isValid) {
$('#view-all').html(res.html)
}
else
$('#form-modal .modal-body').html(res.html);
},
error: function (err) {
console.log(err)
}
})
//to prevent default form submit event
return false;
} catch (ex) {
console.log(ex)
}
}
signalR code (Not finished)
<reference path="../lib/signalr/browser/signalr.js" />
$(() => {
let connection = new signalR.HubConnectionBuilder().withUrl("/signalServer").build();
connection.start();
connection.on("refreshData", function () {
loadData();
});
loadData();
function loadData() {
debugger;
$.ajax({
type: 'GET',
url: '#Url.Action("refreshComments","Home")',
success: function (res) {
$('#view-all').html(res);
}
})
}
});
Code-behind :
var newComment = new CourseComment
{
Comment = comment,
Date = DateTime.Now,
ApplicationUser = user,
SubjectId = subId,
CreatedDate = DateTime.Now
};
_courseCommnt.Entity.Insert(newComment);
await _courseCommnt.SaveAsync();
await _signalR.Clients.All.SendAsync("refreshData");
_toastNotification.AddSuccessToastMessage("تم ارسال التعليق بنجاح");
var courseComments = await _courseCommnt.Entity.GetAll().Include(a => a.ApplicationUser)
.Where(a => a.SubjectId == subId).OrderByDescending(a => a.Date).AsNoTracking().ToListAsync();
var vm = new HomeViewModel
{
CourseComments = courseComments
};
return Json(new
{
isValid = true,
html = Helper.RenderRazorViewToString(this, "_SubjectComments", vm)
});