How I can recognize if there is no internet connection while loading

[assopri]

Hi! I use the following code to download url. But it doesnt throw any exception if internet is disconnected (now I see that just by getting empty source html code of the loaded webpage):

`public virtual void LoadUrlCore(string url)
{
(Browser.RequestHandler as CustomRequestHandler).LastResponceStatusCode = -1;

        if (String.IsNullOrEmpty(url)) return;
      

        var tcs = new TaskCompletionSource<bool>();
        EventHandler<LoadingStateChangedEventArgs> handler = null;
        handler = (sender, args) =>
        {
            
            if (!args.IsLoading)
            {

                Browser.LoadingStateChanged -= handler;

                tcs.TrySetResultAsync(true);
            }
        };
    
        Browser.LoadingStateChanged += handler;

        if (!string.IsNullOrEmpty(url))
        {
            Browser.Load(url);
        }
        
        if (!tcs.Task.Wait(TimeSpan.FromMilliseconds(LoadTimeoutMs)))
            throw new TimeoutException("Время ожидания загрузки страницы истекло");

        if ((Browser.RequestHandler as CustomRequestHandler).LastResponceStatusCode != 200 &&
            (Browser.RequestHandler as CustomRequestHandler).LastResponceStatusCode != -1)
            throw new Exception("Неверный код ответа страницы: " + (Browser.RequestHandler as CustomRequestHandler).LastResponceStatusCode);

    }`

[amaitland]

The LoadError event should be called and provide the relevant error code.

I'd suggest you can use the new LoadUrlAsync method, you can get errors and http status code from the response.

You'll need version 91 for this method.

CefSharp/CefSharp/WebBrowserExtensions.cs

Line 256 in 4e16f3b

public static Task<LoadUrlAsyncResponse> LoadUrlAsync(IWebBrowser chromiumWebBrowser, string url = null, SynchronizationContext ctx = null)

[assopri]

Thank you! I changed like this:

`private string _lastLoadError = "";

    public virtual void LoadUrlCore(string url)
    {
        _lastLoadError = "";

        (Browser.RequestHandler as CustomRequestHandler).LastResponceStatusCode = -1;

        if (String.IsNullOrEmpty(url)) return;
      

        var tcs = new TaskCompletionSource<bool>();

        EventHandler<LoadErrorEventArgs> loadErrorHandler = null;
        EventHandler<LoadingStateChangedEventArgs> loadingStateChangeHandler = null;

        // https://github.com/cefsharp/CefSharp/blob/4e16f3b16dbdedb6f145cbb665b5819906072e21/CefSharp/WebBrowserExtensions.cs#L256
        loadErrorHandler = (sender, args) =>
        {
            if (args.ErrorCode == CefErrorCode.Aborted)
            {
                return;
            }

            Browser.LoadError -= loadErrorHandler;
            Browser.LoadingStateChanged -= loadingStateChangeHandler;
            _lastLoadError = args.ErrorCode.ToString();

            tcs.TrySetResult(true);// new LoadUrlAsyncResponse(args.ErrorCode, -1));
        };

        loadingStateChangeHandler = (sender, args) =>
        {
            
            if (!args.IsLoading)
            {
                //Browser.LoadError -= loadErrorHandler;
                Browser.LoadingStateChanged -= loadingStateChangeHandler;

                tcs.TrySetResultAsync(true);
            }
        };

        Browser.LoadError += loadErrorHandler;
        Browser.LoadingStateChanged += loadingStateChangeHandler;

        if (!string.IsNullOrEmpty(url))
        {
            Browser.Load(url);
        }
        
        if (!tcs.Task.Wait(TimeSpan.FromMilliseconds(LoadTimeoutMs)))
            throw new TimeoutException("Время ожидания загрузки страницы истекло");

        if(!String.IsNullOrEmpty(_lastLoadError)) throw new TimeoutException("Ошибка загрузки страницы: "+ _lastLoadError);

        if ((Browser.RequestHandler as CustomRequestHandler).LastResponceStatusCode != 200 &&
            (Browser.RequestHandler as CustomRequestHandler).LastResponceStatusCode != -1)
            throw new Exception("Неверный код ответа страницы: " + (Browser.RequestHandler as CustomRequestHandler).LastResponceStatusCode);

    }

`

However I still face situation that LoadingStateChanged is hooked earlier than LoadError.

[amaitland]

What exactly is stopping you from upgrading to version 91?

[assopri]

Ok I already upgraded. How can I update my original function to use LoadUrlAsync . How I extract LoadError from it's return value without await and changing my caller function ( LoadUrlCore ) to async?

public virtual void LoadUrlCore(string url)
        {
            _lastLoadError = "";

            (Browser.RequestHandler as CustomRequestHandler).LastResponceStatusCode = -1;

            if (String.IsNullOrEmpty(url)) return;
          
            var tcs = new TaskCompletionSource<bool>();

            EventHandler<LoadingStateChangedEventArgs> loadingStateChangeHandler = null;

            loadingStateChangeHandler = (sender, args) =>
            {                
                if (!args.IsLoading)
                {
                    Browser.LoadingStateChanged -= loadingStateChangeHandler;

                    tcs.TrySetResultAsync(true);
                }
            };

            Browser.LoadingStateChanged += loadingStateChangeHandler;

            if (!string.IsNullOrEmpty(url))
            {
                Browser.LoadUrlAsync(url);
            }
            
            if (!tcs.Task.Wait(TimeSpan.FromMilliseconds(LoadTimeoutMs)))
                throw new TimeoutException("Время ожидания загрузки страницы истекло");

            if(!String.IsNullOrEmpty(_lastLoadError)) throw new TimeoutException("Ошибка загрузки страницы: "+ _lastLoadError);

            if ((Browser.RequestHandler as CustomRequestHandler).LastResponceStatusCode != 200 &&
                (Browser.RequestHandler as CustomRequestHandler).LastResponceStatusCode != -1)
                throw new Exception("Неверный код ответа страницы: " + (Browser.RequestHandler as CustomRequestHandler).LastResponceStatusCode);

        }

[amaitland]

You can obtain the Error code and http status code from the response.

http://cefsharp.github.io/api/91.1.x/html/M_CefSharp_IWebBrowser_LoadUrlAsync.htm
http://cefsharp.github.io/api/91.1.x/html/T_CefSharp_LoadUrlAsyncResponse.htm

[assopri]

Thank you! That works just fine