I am trying to add some caching to a WebView for a Windows Phone 8.1 WinRT application. I am using the new IUriToStreamResolver to get streams for certain urls and this works OK most of the time. For some urls I get the following exception though:
System.Runtime.InteropServices.COMException (0x80004005): Error HRESULT E_FAIL has been returned from a call to a COM component. at System.Threading.Tasks.TaskToAsyncOperationAdapter
1.OnCompleted(AsyncOperationCompletedHandler1 userCompletionHandler, AsyncStatus asyncStatus) at System.Threading.Tasks.TaskToAsyncInfoAdapter4.OnCompletedInvoker(AsyncStatus status) at System.Threading.Tasks.TaskToAsyncInfoAdapter4.TaskCompleted() --- End of stack trace from previous location where exception was thrown --- at System.Threading.Tasks.ExceptionDispatchHelper.b__1(Object edi) at System.Threading.QueueUserWorkItemCallback.WaitCallback_Context(Object state) at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx) at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx) at System.Threading.QueueUserWorkItemCallback.System.Threading.IThreadPoolWorkItem.ExecuteWorkItem() at System.Threading.ThreadPoolWorkQueue.Dispatch() at System.Threading._ThreadPoolWaitCallback.PerformWaitCallback()
My UriToStreamResolver uses System.Net.HttpClient to get data from the web and convert the relative url to an absolute URL.
using System;
using System.Threading.Tasks;
using Windows.Foundation;
using Windows.Storage.Streams;
using Windows.Web;
namespace OfflineBrowser
{
public sealed class StreamUriWinRTResolver : IUriToStreamResolver
{
readonly System.Net.Http.HttpClient _httpClient = new System.Net.Http.HttpClient();
private readonly string _baseUrl;
public StreamUriWinRTResolver(string baseUrl)
{
_baseUrl = baseUrl;
}
public IAsyncOperation<IInputStream> UriToStreamAsync(Uri uri)
{
try
{
if (uri == null)
{
throw new Exception();
}
string path = uri.AbsolutePath;
return GetContent(path).AsAsyncOperation();
}
catch (Exception)
{
return null;
}
}
private async Task<IInputStream> GetContent(string uriPath)
{
try
{
var url2 = _baseUrl + uriPath;
var bytes = await _httpClient.GetByteArrayAsync(new Uri(url2));
IInputStream inputStream = await GetStreamForByteArray(bytes);
return inputStream;
}
catch (Exception)
{
//catch not working..
return null;
}
}
private static async Task<IInputStream> GetStreamForByteArray(byte[] content2)
{
var ras = new InMemoryRandomAccessStream();
var datawriter = new DataWriter(ras);
datawriter.WriteBytes(content2);
await datawriter.StoreAsync();
await datawriter.FlushAsync();
return ras.GetInputStreamAt(0);
}
}
}
I call it like this:
private async void Button_Click(object sender, RoutedEventArgs e)
{
Uri MyUrl = WebView.BuildLocalStreamUri("MyContent", "/tvgids");
StreamUriWinRTResolver MyResolver = new StreamUriWinRTResolver("http://www.nu.nl");
WebView.NavigateToLocalStreamUri(MyUrl, MyResolver);
}
I tried catching the exception but that doesn't work either. What could be wrong here? I encounter the error both in simulator and on a real device. Thanks for reading.
