How to update a razorPage Async with new data

Question

Problem: I want to monitor incoming data from a subscription without having to refresh the page.

Using RazorPages.

At the minute I have a very simple app:

(code behind)

public class PageModel
{ 
     public List<string> dataList = new List<string>();

     public void OnGet()
     {
        var mySubscriber = Subscriber.subscribe(actionMethod);
     }

    private async Task actionMethod(string data)
    {
          dataList.Add(data);
    }
}

(page)

@foreach(var s in Model.dataList){
  <div>@s</div>
}

The subscriber calls the actionMethod whenever a new string is received.

However currently, this is static and once the page loads, I have to refresh the page to get more data.

How to refactor this so that the page automatically updates with new data?

razor is an HTML generator from templates, so you can use html and js freely there. use long polling requests using JS `setInterval` and ajax requests to get the data — CME64, Mar 13 '19 at 14:34

score 0 · Answer 1 · answered Mar 13 '19 at 14:44

0

You can't do it without refresh, becouse Razor tec isn't bidirectional. In asp.net (or core) u can use SignalR.

Link to MSDN manual

answered Mar 13 '19 at 14:44

Denis Lightman

53
5

score 0 · Answer 2 · answered Mar 13 '19 at 14:58

You have to make some AJAX calls periodically on the UI to update your view. As @Denis mentioned in his answer, SignalR might be a solution, but this is more for notifications. In your case, it seems to me that you will have to perform this call once in a while to refresh some data that you display.

If there is just a portion of your display that you want to update, you could use a Partial View. Here is a thread on this matter.

How to update a razorPage Async with new data

2 Answers2