MVC在不可预知的时间从razor @Helper调用Javascript

Question

In my MVC view I need to get razor c# code to execute a javascript function at unpredictable times, way after the page has loaded.

I have used a thread to simulate unpredictableness but ultimately instead of the thread it will be a WCF callback method that raises an event which runs the helper, but to eliminate session issues I have used the thread.

Javascript to execute:

<script type="text/javascript">
    function DisplayNews(news) {
        alert(news);
    }
</script>

Helper that runs the javascript (because sticking this directly in the below thread didn't work)

@helper UpdateNews(string news)
{          
    <script>
        DisplayNews(news);
    </script>   
}

Thread that simulates unpredictableness/post page loading or non user invoked events

@{
    System.Threading.Thread T = new System.Threading.Thread(new System.Threading.ThreadStart(delegate
    {
        while (true)
        {
            System.Threading.Thread.Sleep(5000);
            UpdateNews("Some cool news");        
        }
    }));

    T.Start();
}

If I stick a break point at UpdateNews("Some cool news"); I can see that it gets hit every 5 seconds as it should, but thats as far as it gets, nothing else happens. I can't stick a break point in the helper or the Javascript so I can't see where it stops working after that.

Is this going to work at all or is there another way I should be approaching this?

Any help would be greatly appreciated.

Answer 1

In server side code you can call an client function...

Razor executed in server side and javascript is in client side.that mean when you get server response it's created by razor code in server side and now you can just use javascript in client side

Answer 2

I may be misunderstanding what you are trying to do but you can have javascript that will run on page load that will be wrapped in a set timeout with a random millisecond period.

Something like this:

<script>
  window.onload = function() {
     setTimeout(function() {}, 1000); // this will run 1 second after page load
  }
</script>

simply randomize the number being passed as the second parameter to setTimeout and your javascript will run at a random time after the page loads.