How to handle WPF WebBrowser control navigation exception

Question

Let\'s say that WPF WebBrowser control shows some navigation errors and the page is not showing.

So there is an exception of WPF WebBrowser contro

Answer 1

I'd been struggling with this issue for some time. I discovered a cleaner way to handle this than the accepted answer. Checking for res://ieframe.dll didn't always work for me. Sometimes the document url is null when a navigation error happened.

Add the following References to you project:

1. Microsoft.mshtml
2. Microsoft.VisualStudio.OLE.Interop
3. SHDocVw (Under COM it's called "Microsoft Internet Controls")

Create the following helper class:

using System;
using System.Diagnostics.CodeAnalysis;
using System.Runtime.InteropServices;
using System.Windows.Controls;
using System.Windows.Navigation;

/// 

/// Adds event handlers to a webbrowser control
/// 
internal class WebBrowserHelper
{
    [SuppressMessage("StyleCop.CSharp.NamingRules", "SA1310:FieldNamesMustNotContainUnderscore", Justification = "consistent naming")]
    private static readonly Guid SID_SWebBrowserApp = new Guid("0002DF05-0000-0000-C000-000000000046");

    internal WebBrowserHelper(WebBrowser browser)
    {
        // Add event handlers
        browser.Navigated += this.OnNavigated;

        // Navigate to about:blank to setup the browser event handlers in first call to OnNavigated
        browser.Source = null;
    }

    internal delegate void NavigateErrorEvent(string url, int statusCode);

    internal event NavigateErrorEvent NavigateError;

    private void OnNavigated(object sender, NavigationEventArgs e)
    {
        // Grab the browser and document instance
        var browser = sender as WebBrowser;
        var doc = browser?.Document;

        // Check if this is a nav to about:blank
        var aboutBlank = new Uri("about:blank");
        if (aboutBlank.IsBaseOf(e.Uri))
        {
            Guid serviceGuid = SID_SWebBrowserApp;
            Guid iid = typeof(SHDocVw.IWebBrowser2).GUID;

            IntPtr obj = IntPtr.Zero;
            var serviceProvider = doc as Microsoft.VisualStudio.OLE.Interop.IServiceProvider;
            if (serviceProvider?.QueryService(ref serviceGuid, ref iid, out obj) == 0)
            {
                // Set up event handlers
                var webBrowser2 = Marshal.GetObjectForIUnknown(obj) as SHDocVw.IWebBrowser2;
                var webBrowserEvents2 = webBrowser2 as SHDocVw.DWebBrowserEvents2_Event;
                if (webBrowserEvents2 != null)
                {
                    // Add event handler for navigation error
                    webBrowserEvents2.NavigateError -= this.OnNavigateError;
                    webBrowserEvents2.NavigateError += this.OnNavigateError;
                }
            }
        }
    }

    /// 

    /// Invoked when navigation fails
    /// 
    [SuppressMessage("StyleCop.CSharp.NamingRules", "SA1305:FieldNamesMustNotUseHungarianNotation", Justification = "consistent naming")]
    [SuppressMessage("StyleCop.CSharp.NamingRules", "SA1306:FieldNamesMustBeginWithLowerCaseLetter", Justification = "consistent naming")]
    private void OnNavigateError(object pDisp, ref object URL, ref object Frame, ref object StatusCode, ref bool Cancel)
    {
        this.NavigateError.Invoke(URL as string, (int)StatusCode);
    }
}

Then in your window class:

// Init the UI
this.InitializeComponent();
this.WebBrowserHelper = new WebBrowserHelper(this.MyBrowserPane);

// Handle nav error
this.WebBrowserHelper.NavigateError += this.OnNavigateError;