Graphics Layer inaccessible by background thread

[dipinbehl]

Hi All,

I am using ArcGis API for WPF in a desktop based application to show locations, route for the stops on a 2D Map.
A background thread fetches the locations (along with lat-long) from a WCF service. Then these locations are displayed on the Map as TextSymbol(s) on a GraphicLayer.
Then another background thread calls a WCF RESTfull resource to find route for the locations (stops). This call returns me a route which i am trying to display on the map using another GraphicLayer using 'Add' method of the 'Graphics' property of the layer. Whenever i try to do so, i get an exception 'The calling thread cannot access this object because a different thread owns it.'
I have tried to use Dispatcher object for the screen, the map object, the graphics layer but none seems to work for me.

[klugerama]

I have tried to use Dispatcher object for the screen, the map object, the graphics layer but none seems to work for me.

Can you post the code that you are using to accomplish this? What error do you get when you attempt to use the Dispatcher?

[apurva.goyal]

Can you post the code that you are using to accomplish this? What error do you get when you attempt to use the Dispatcher?

I am getting similar error on my WPF application. Here is the code I am using-

BackgroundWorker worker = new BackgroundWorker();
worker.WorkerSupportsCancellation = true;
//this is where the long running process should go
worker.DoWork += (o, ea) =>
{
ea.Result = ReadShapeFileAsGraphics(droppedFilePaths[0]);
};
worker.RunWorkerCompleted += (o, ea) =>
{
IEnumerable<Graphic> graphics = ea.Result as IEnumerable<Graphic>;
Dispatcher.CurrentDispatcher.Invoke((System.Action)(() =>
{
if (graphics.Count() > 0)
foreach (Graphic g in graphics)
GraphicLayer.GraphicsSource = graphics;

}));

//work has completed. you can now interact with the UI
IsBusy = false;
};
//set the IsBusy before you start the thread
IsBusy = true;
worker.RunWorkerAsync();

Thanks

Apurva

[klugerama]

There are two issues here:

                                    if (graphics.Count() > 0)
                                        foreach (Graphic g in graphics)
                                            GraphicLayer.GraphicsSource = graphics;

This should be:

                                    if (graphics.Count() > 0)
                                        GraphicLayer.GraphicsSource = graphics;

Secondly, and more importantly:

                            Dispatcher.CurrentDispatcher.Invoke((System.Action)(() =>

...should be:

                            Dispatcher.CurrentDispatcher.Invoke((System.Action)((graphics) =>