I'm not too familiar with signalr2 on asp.net-core pardon me, am trying to create a POC on how to implement a real-time CRUD application with admin and client using signalr2, but am having issues with signalr data push, I keep getting NullReferenceException: Object reference not set to an instance of an object.
on this line await Clients.All.SendAsync("BroadcastData", data);
Below is how I setup my Hub using some online examples I looked-up:
public class OddPublisher : Hub
{
private readonly IOddServices _oddService;
public OddPublisher(IOddServices oddService)
{
_oddService = oddService;
}
public async Task BroadcastData()
{
var data = _oddService.ClientQueryOdds();
await Clients.All.SendAsync("BroadcastData", data); //breaks here
}
}
and this is triggered by admin, on submiting and saving the data sucessfully I call the BroadcastData()
public class BaseController : Controller
{
public IOddServices _oddService;
public readonly OddPublisher _publisher;
public BaseController(IOddServices oddService, )
{
_oddService = oddService;
_teamService = teamService;
_publisher = new OddPublisher(oddService);
}
[HttpPost]
public async Task<IActionResult> odd_entry(CreateOdd dto)
{
//somecode here...
var results = _validator.Validate(dto);
if(!results.IsValid)
{
results.AddToModelState(ModelState, null);
return View(dto);
}
_oddService.CreateOddAndTeam(dto);
await _publisher.BroadcastData(); //Breaks
return RedirectToAction(nameof(index));
}
}
Folled all the instructions as adviced in Microsoft Asp.Net Core Signalr Documentation, my Startup has all required sevices added.
here is the client and the JS file,
"use strict";
var connection = new signalR.HubConnectionBuilder().withUrl("/oddPublisher").build();
connection.on("BroadcastData", data => {
console.table(data);
//getAll();
})
connection.start().then(function () {
getAll();
}).catch(function (err) {
return console.error(err.toString());
});
function getAll() {
var model = $('#dataModel');
$.ajax({
url: '/home/GetLatestOddData',
contentType: 'application/html ; charset:utf-8',
type: 'GET',
dataType: 'html',
success: function (result) { model.empty().append(result); }
});
}
Need some help here guys, I still don't know what am doing wrong, I'll really appreciate if I can get any help on this.
Thank you in advance.
事实证明我需要将IHubContext注入我的集线器才能访问客户端。
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