Question

I am using imagery service to get an image from bing maps, and from time to time my apllication used to quit without a reason, I figured out that it’s because imagery service is not handling the mapuri request timeout.

Get Image:

    public static void GetBingMapImage(double longitude, double latitude, Size size, int zoomLevel, ImageryServiceParams imageResponseCallback)
    {
        var mapUriRequest = new MapUriRequest();
        var location = new GeocodeLocation { Latitude = latitude, Longitude = longitude };

        // Set credentials using a valid Bing Maps key
        mapUriRequest.Credentials = new Credentials();
        mapUriRequest.Credentials.ApplicationId = BingMapsKey;

        // Set the location of the requested image
        mapUriRequest.Center = new GeocodeLocation();
        mapUriRequest.Center.Latitude = location.Latitude;
        mapUriRequest.Center.Longitude = location.Longitude;

        mapUriRequest.Pushpins = new ObservableCollection<ImageryService.Pushpin>();
        mapUriRequest.Pushpins.Add(new ImageryService.Pushpin { Location = location, IconStyle = "10" });
        // Set the map style and zoom level
        var mapUriOptions = new MapUriOptions();
        mapUriOptions.Style = MapStyle.AerialWithLabels;
        mapUriOptions.ZoomLevel = zoomLevel;

        // Set the size of the requested image to match the size of the image control
        mapUriOptions.ImageSize = new SizeOfint();
        mapUriOptions.ImageSize.Height = Convert.ToInt16(size.Height);
        mapUriOptions.ImageSize.Width = Convert.ToInt16(size.Width);

        mapUriRequest.Options = mapUriOptions;

        var imageryService = new ImageryServiceClient("BasicHttpBinding_IImageryService");
        imageryService.GetMapUriCompleted += ImageryServiceGetMapUriCompleted;

        imageryService.GetMapUriAsync(mapUriRequest, imageResponseCallback);
    }

Response here:

        public MyApplication.ImageryService.MapUriResponse EndGetMapUri(System.IAsyncResult result) {
            object[] _args = new object[0];
            MyApplication.ImageryService.MapUriResponse _result = ((MyApplication.ImageryService.MapUriResponse)(base.EndInvoke("GetMapUri", _args, result)));
            return _result;

The exception:

The HTTP request to ‘http://dev.virtualearth.net/webservices/v1/imageryservice/imageryservice.svc’ has exceeded the allotted timeout of 00:01:00. The time allotted to this operation may have been a portion of a longer timeout.

You can easily reproduce this by putting a break point after the request and waiting there about a minute or so.

What should I do to handle this exception, I didn’t find any solution, nor question related to this topic…

I’m also talking about this problem here: http://forums.create.msdn.com/forums/p/103502/616465.aspx#616465

Thanks in advance.

Answer 1

Handling the exception in the getImageryCompleted event seemed to fix this problem:

        private static void ImageryServiceGetMapUriCompleted(object sender, GetMapUriCompletedEventArgs e) 
        { 
// This is where you want to handle the timeout or web service errors.  This will prevent
// the error that the debugger stops on from getting back to the main thread and from your
// application having an UnhandledException.
try
{
            if (e.Result == null) return; 

            var imageryServiceParams = e.UserState as ImageryServiceParams; 
            if (imageryServiceParams != null) 
                imageryServiceParams.ImageResponseCallback.DynamicInvoke(new ImageryServiceResult(new Uri(e.Result.Uri, UriKind.Absolute)) { UserState = imageryServiceParams.UserState }); 
          }
catch
{
// The "MessageBox.Show is in a try/catch since it throws an exception if it is called when another
// MessageBox.Show is open. This was at least the case in Pre-Mango releases.
try { MessageBox.Show("Caught the TimeOut or WebException.  Application still running."); }
catch {}
}