Hi,
I would like to add ZedGraphs to the features within my Map, I have used the sample code with success and would like to implement the functionality within my own application. Here is the code I am using (based upon the sample code) :
The CreateZed() function is called after the features are retrieved from a database.
private ZedGraphStyle CreateZed(WpfMap pMap)
{
ZedGraphStyle zed = new ZedGraphStyle();
zed.ZedGraphDrawing += ZedGraphStyle_ZedGraphDrawing;
return zed;
}
private delegate Bitmap ToUIThreadDelegate(WpfMap pMap, ZedGraphDrawingEventArgs e);
private void ZedGraphStyle_ZedGraphDrawing(object pSender, ZedGraphDrawingEventArgs pE)
{
pE.Bitmap = (Bitmap) Dispatcher.CurrentDispatcher.Invoke
(
new ToUIThreadDelegate(ZedGraphDrawing), new object[] { pE.Feature.Tag, pE }
);
}
private Bitmap ZedGraphDrawing(WpfMap pMap, ZedGraphDrawingEventArgs pE)
{
double scale = ExtentHelper.GetScale(pMap.CurrentExtent, (float) pMap.Width, GeographyUnit.DecimalDegree);
// Change the size of the graph based on the scale. It will get bigger as you zoom in.
int graphHeight = Convert.ToInt32(100000000 / scale);
// After this, the code from the sample is pasted / used, nothing interesting.
}
My problem is that I need to access the Map I am currently building in one way or the other. I've tried to do so by adding a Tag to my Features with the WpfMap which is displayed. The reason I am trying to achieve this is that I would like the charts to be, as within the sample, zoom level dependent.
The Sample contained "Dispatcher.Invoke" yet this didn't work, so I added "Dispatcher.CurrentDispatcher" instead. I've also tried to access the WpfMap that is being created via the "map" parameter, to no avail.
I must say that the code is fully functional (e.g. graphs are being displayed over the features), if the "scale" variable is given a hardcoded value.
Since the delegate creates a new Thread, I immediately receive a "System.InvalidOperationException" Except, stating "The calling thread cannot access this object", since it resides in another thread. The same thing (obviously) happens when I try to store the WpfMap within my current class.
Is there a workaround ? The "Sender" Parameter from the EventHandler only points to the ZedGraphStyle Object created earlier. I am using ThinkGeo 4.5 Desktop WPF Edition, within a .NET 3.5 context.
Or is there another way to get the scale and implement a zoom level dependent graph scaling ?
Thank you in advance !
