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Remove a dead lock in the Internet Explorer on Thread.Sleep?

I know all browsers are single threaded and impossible implements in JavaScript or Flash Player Thread.sleep. I decided to try using “System.Threading” library implements Thread.Sleep in the Silverlight.

App.xaml.cs

using System.Windows;
using System.Windows.Browser;
using System.Threading;

namespace ThreadSleep
{
    public partial class App : Application
    {

        public App()
        {
            InitializeComponent();
            HtmlPage.RegisterScriptableObject("App", this);
        }

        [ScriptableMember]
        public void Sleep(int mlsec)
        {
            Thread.Sleep(mlsec);
        }
    }
}

So, from a JavaScript code I can execute a Sleep function, but my Internet Explorer freeze and not responding.

Here is my example:

Index.html

<HTML>
<BODY>
<SCRIPT LANGUAGE="JavaScript">
<!--
    var SleepInterval = 10000;

    function pause1(){
        window.showModalDialog("PauseWin.html", this, 'dialogWidth:255px; dialogHeight:105px; status:0; scroll:0;');
        alert("Resume");
    }
    function pause2(){
        var control = document.getElementById("SleepSL");
        control.Content.App.Sleep(SleepInterval);
        alert("Resume");
    }
    function tick(){
        var clock = document.getElementById("clock");
        if(clock) clock.innerHTML = new Date();
    }
    setInterval(tick, 1000);
//-->
</SCRIPT>
<INPUT TYPE="button" value="Pause Modal Dialog" onclick="pause1()">
<INPUT TYPE="button" value="Pause Thread Sleep" onclick="pause2()">
<BR><BR>

<!--Youtube Video -->
<iframe title="YouTube video player" width="640" height="390" src="http://www.youtube.com/embed/RWNcGBSP0Wg?autoplay=1" frameborder="0" allowfullscreen></iframe>

<!-- Silverlight Sleep API -->
<object id="SleepSL" data="data:application/x-silverlight-2," type="application/x-silverlight-2" width="1" height="1">
    <param name="source" value="SleepSL.xap"/>
    <param name="background" value="white" />
    <param name="minRuntimeVersion" value="4.0.50826.0" />
    <param name="autoUpgrade" value="true" />
    <a href="http://go.microsoft.com/fwlink/?LinkID=149156&v=4.0.50826.0" style="text-decoration:none">
        <img src="http://go.microsoft.com/fwlink/?LinkId=161376" alt="Get Microsoft Silverlight" style="border-style:none"/>
    </a>
</object>
<BR><BR>

<DIV ID="clock"/>
</BODY>
</HTML>

PauseWin.html

<html>
<title>Pause Window</title>
<style>body{margin-top:10}</style>
<body scroll="no">

<center style='fon开发者_开发问答t-size:14px;font-weight:bold'>
    The window will automatically <br> close in <span id="time"></span>&nbsp;second(s).
</center>

<script type="text/javascript">
    var ms = window.dialogArguments.SleepInterval;

    function wait(){
        var span = document.getElementById('time');
        span.innerHTML = (ms / 1000);
        setInterval(function(){ closeWindow(); }, ms);
        setInterval(function(){ ms -= 1000; if(ms > 0) span.innerHTML = (ms / 1000); }, 1000);
    }

    function closeWindow(){
        window.close()
    }
    wait();
</script>
</body>
</html>

By executing an index.html file I am starting a YouTube video and timer. When I pressed "Pause Modal Dialog" the timer stops, but video continue playing, after 10 seconds the Modal Popup window destroying by JS “window.close()” and in my code I am going to the next line and executing alert(“Resume”). Nothing change the video continues playing. Now if I will press "Pause Thread Sleep" button using a Silverlight Thread.Sleep function. At this time video will hang and by clicking on the Internet Explorer you may get (Not Responded) state in the Process Explorer.

I will prefer to use Thread.Sleep function in the COM, ActiveX or Silverlight objects, but I need to remove that a thread dead lock. Get the same behavior as in JavaScript Modal Dialog or Alert.

Many thanks in advance.

Regards,

David Gofman

Code:

index.html

PauseWin.html


Your code is doing exactly what you're telling it to do: it's sleeping your browser's UI thread, which means that your browser can't process any more messages, so it's effectively hanging your browser for the duration of the sleep. Thread.Sleep() in a browser is death: just don't do it, whether in Silverlight or any other framework.

A better approach would be to step back and ask yourself why you want to sleep something, and then figure out a reasonable async way of doing that. Having been thrown into the Silverlight async world several years ago, I realize that this can be disorienting at first, but I can also testify that I've always found reasonably clean ways to do it right.

Another way to put it: if you can't figure out how to do what it is that you actually need to get done, post a question about that, and you'll likely get some help here.

For instance, if you just want to wait 'n' seconds and then perform a callback, you could use a helper class like this one:

public class ThreadingHelper
{
    public static void SleepAsync(int millisecondsToSleep, Action action)
    {
        var timer = new Timer(o => action());
        timer.Change(millisecondsToSleep, Timeout.Infinite);
    }

    public static void SleepAsync(TimeSpan interval, Action action)
    {
        SleepAsync((int)interval.TotalMilliseconds, action);
    }

    public static void DispatcherSleepAsync(int millisecondsToSleep, Action action)
    {
        var interval = TimeSpan.FromMilliseconds(millisecondsToSleep);
        DispatcherSleepAsync(interval, action);
    }

    public static void DispatcherSleepAsync(TimeSpan interval, Action action)
    {
        var timer = new DispatcherTimer();
        EventHandler timerHandler = null;
        timerHandler = (s, e) =>
        {
            timer.Tick -= timerHandler;
            if (action != null)
            {
                action();
            }
        };
        timer.Tick += timerHandler;
        timer.Interval = interval;
        timer.Start();
    }

}


You could do this:

function begin() { /* do stuff... */ }
function afterWait() { /* rest of my code...*/ }

begin();
setTimeout(afterWait, 10000);

setTimeout has effectively stopped your javascript for 10 seconds, and the browser can still carry on working

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