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Webbrowser Error "Channel disconnected" on Windows 10 Enterprise LTSB Options
Riephi
Posted: Tuesday, March 6, 2018 12:36:39 PM
Rank: Advanced Member
Groups: Member

Joined: 7/17/2015
Posts: 51
Dear Support Team,

I installed our software with your Webbrowser version 18.0.15.0 on a VMWare with Windows 10 Enterprise LTSB. Loading any URLs doesn't work. I very often get error "Channel disconnected".

Do you know this issue? Or could it be, that win 10 Enterprise LTSB is not supported?

After getting this error the webview is stuck and I can't reload the URL. Due to this case I catch this error and I have to intitialize webview again (see Code below).

You can reproduce it this way (see code below):

NavigateToActiveConnection(firstBackendUrl) (works in most cases) -> NavigateToActiveConnection(newBackendUrl) -> "Channel disconnected"

My code looks like this:
Code: C#
private void WebViewException(object sender, EO.Base.ExceptionEventArgs e)
{
    if (e.ErrorException.Message.Equals("Channel disconnected"))
    {
        NavigateToActiveConnection(backendSystemUrl);
    }
}


Code: C#
private void NavigateToActiveConnection(string url)
{
    if(!firstLoad) {
        webView.Engine.Stop(true);
        webView.Destroy();
        webView = new EO.Wpf.WebView();
        webControl.WebView = webView;
        CustomizeWebView(); // do webview settings

       webView.LoadUrl(url);
    }
    else 
    {
        webView.LoadUrl(url);
        firstLoad = false;
    }
}


This only happens on my Win 10 Enterprise LTSB WM.

On other systems (Win 7, Win 8, Win 8.1, Win 10) we didn't had this problem until now.

Another question is: do I really need to destroy webview and initialize it again to clear cache and cookies? I need to clear it, because we have different users on our backend systems. It could be the case, that the same URL is loaded, but with outher credentials. If I could clear cache/ cookie another way, I wouldn't need to destroy webview each time I load a new URL.


Do you know any fix for this issue?

Thanks in advance!

Best regards
eo_support
Posted: Tuesday, March 6, 2018 3:38:10 PM
Rank: Administration
Groups: Administration

Joined: 5/27/2007
Posts: 24,221
Hi,

Currently we do not have a Windows LTSB system for testing on this issue. You can try the steps here and see if it resolves the issue:

https://www.essentialobjects.com/doc/common/eowp.aspx

If that does not resolve the issue, please try to collect crash report (or enable automatic crash report):

https://www.essentialobjects.com/doc/common/crash_report.aspx

If none of the above work, then it would be very helpful if you can setup a LTSB system that demonstrates this problem and allow us to remotely connects to it to investigate further.

As to destroying WebView, yes you do need to destroy all WebView in order to clear cache and cookies. However here "all" only means all WebView for the same engine. Each engine uses a different cache folder (thus also maintain different caches). So clearing cache/cookie is on Engine level. As such if you have multiple Engines for multiple users, then each engine can be stopped independently without affect other Engines and WebViews associated to those Engine object. See here for more details:

https://www.essentialobjects.com/doc/webbrowser/advanced/engine.aspx

Additionally, we do not encourage trying to restart Engine as a way to recover the WebView inside your Exception event handler. This is because this handler can be called by background thread and you should NOT create your WebView inside a background thread. See here for more details:

https://www.essentialobjects.com/doc/webbrowser/start/webview_no_ui.aspx

If you do need to recover, you should at least have additional code to make sure that the recovering logic runs in your UI thread.

It is not necessary to call WebView.Destroy after you call Engine.Stop because Engine.Stop will destroy all WebViews associated to that engine.

Hope this helps.

Thanks!
Riephi
Posted: Thursday, March 8, 2018 9:04:04 AM
Rank: Advanced Member
Groups: Member

Joined: 7/17/2015
Posts: 51
Hi,

thanks for your quick reply!

The problem was stopping the engine and restarting it before loading a new URL. I removed this and now it is working on LTSB, too. I don't know why, but we only had this issue on this OS.
I also tried to collect some crash report, but there was no crash.

Now we clear cache and cookies in our web application. So I do not have to stop the engine anymore, before loading a new URL.

Thanks!
JASS
Posted: Thursday, March 8, 2018 2:08:09 PM
Rank: Newbie
Groups: Member

Joined: 3/8/2018
Posts: -1
Philipp Rieder wrote:
Hi,

thanks for your quick reply!

The problem was stopping the engine and restarting it before loading a new URL. I removed this and now it is working on LTSB, too. I don't know why, but we only had this issue on this OS.
I also tried to collect some crash report, but there was no crash.

Now we clear cache and cookies in our web application. So I do not have to stop the engine anymore, before loading a new URL.

Thanks!





SORRY TO SAY I HAVE A STILL PROBLEM
eo_support
Posted: Thursday, March 8, 2018 3:45:51 PM
Rank: Administration
Groups: Administration

Joined: 5/27/2007
Posts: 24,221
Philipp Rieder wrote:
Hi,

thanks for your quick reply!

The problem was stopping the engine and restarting it before loading a new URL. I removed this and now it is working on LTSB, too. I don't know why, but we only had this issue on this OS.
I also tried to collect some crash report, but there was no crash.

Now we clear cache and cookies in our web application. So I do not have to stop the engine anymore, before loading a new URL.

Thanks!


Thanks for sharing. I am glad that you have found a workaround. We do not know why this occurs yet. We will keep an eye on it and if we have any new information we will reply here again.
eo_support
Posted: Thursday, March 8, 2018 3:48:52 PM
Rank: Administration
Groups: Administration

Joined: 5/27/2007
Posts: 24,221
JASS wrote:
SORRY TO SAY I HAVE A STILL PROBLEM


You problem may be different than the original post. In the original post the problem only occurs to LTSB systems. You can follow the steps outlined in our first reply and see if that resolves the issue for you. If that still does not resolve the issue, please try to isolate the problem into a test project and send the test project to us:

https://www.essentialobjects.com/forum/test_project.aspx

If the problem is not reproducible elsewhere, then please check if you can get any crash report first. If there is no crash report, then we may need to remotely connect to the computer that has problem in order to investigate further.

Thanks!


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