Blank Screen

[GMCadiom]

• What version of the product are you using?

  • Nuget v104.4.240

• What architecture x86 or x64?
  x86 & x64

• What version of .Net?
  .Net 4.8

• On what operating system?
  Win10

• Are you using WinForms, WPF or OffScreen?
  WinForms

• Does this problem also occur in the CEF Sample Application
  Yes

NOW

I want to join group in Whatsapp site
and when I

CefBrowser.ExecuteScriptAsync("document.getElementsByClassName('_9vcv _advm')[0].click()");

I got blank screen

and when do the same in google chrome it works fine
my full code is

        public ChromiumWebBrowser CefBrowser;
        public CefSettings CefBrowserSettings = new CefSettings();
        public Form1()
        {
            InitializeComponent();
            InitializeCef();
        }

        public void InitializeCef()
        {
            try
            {
                if (tableLayoutPanel1.Controls.Contains(CefBrowser))
                    tableLayoutPanel1.Controls.Remove(CefBrowser);

                CefBrowser = new ChromiumWebBrowser() { Dock = DockStyle.Fill, Enabled = true };
                if (!Cef.IsInitialized)
                {
                    CefBrowserSettings = new CefSettings();
                    CefBrowserSettings.RemoteDebuggingPort = 8080;
                    CefBrowserSettings.UserDataPath = Session.SessionUserDataPath();
                    CefBrowserSettings.CachePath = Session.SessionCachePath();
                    Cef.EnableWaitForBrowsersToClose();
                    Cef.Initialize(CefBrowserSettings, performDependencyCheck: true, browserProcessHandler: null);
                }
                else
                {
                    var requestContextSettings = new RequestContextSettings { CachePath = Session.SessionCachePath() };
                    CefBrowser.RequestContext = new RequestContext(requestContextSettings, new RequestContextHandler());
                }

                tableLayoutPanel1.Controls.Add(CefBrowser, 1, 0);
                CefBrowser.Load("https://chat.whatsapp.com/ELbawvyysfmFb2KTHcqm2V");
            }
            catch (Exception ex)
            {
            }
        }

        //Join Group Button
        private void button3_Click(object sender, EventArgs e)
        {
            CefBrowser.ExecuteScriptAsync("document.getElementsByClassName('_9vcv _advm')[0].click()"); <<< Error Here 
        }

any idea how to fix it ?

thanks in advance

[amaitland]

Check the log file for errors see https://github.com/cefsharp/CefSharp/wiki/Trouble-Shooting#log-file

Also calling Cef.Initialize needs to happen before you create your first ChromiumWebBrowser instance. Your code needs a reorder.

I'd also suggest subscribing to the LoadError event as a blank page is often a page load failure. See https://github.com/cefsharp/CefSharp.MinimalExample/blob/master/CefSharp.MinimalExample.WinForms/BrowserForm.cs#L39 for example

[GMCadiom]

Thanks for comment ,
I will try and post the results and updates

[GMCadiom]

I have checked the log and this the results :
Failed to load URL whatsapp://chat/?code=Jv4c1BnA9Qf94GD3vRG4L4 with error ERR_UNKNOWN_URL_SCHEME (UnknownUrlScheme).

[amaitland]

If the website is attempting to navigate to the given url then you can try canceling the navigation.

public class CustomRequestHandler : CefSharp.Handler.RequestHandler
{
	protected override bool OnBeforeBrowse(IWebBrowser chromiumWebBrowser, IBrowser browser, IFrame frame, IRequest request, bool userGesture, bool isRedirect)
	{
		//Cancel
		if (request.Url.StartsWith("whatsapp:"))
		{
			//Cancel the request 
			return true;
		}
		return base.OnBeforeBrowse(chromiumWebBrowser, browser, frame, request, userGesture, isRedirect);
	}
}

browser.RequestHandler = new CustomRequestHandler();

[GMCadiom]

That's worked perfectly, thanks a lot.