topic Re: ConstrainExtentBehavior bug? in ArcGIS API for Silverlight Questions

ConstrainExtentBehavior bug?

EricO_Neal — Fri, 03 Dec 2010 14:58:06 GMT

My "Draw" tool for drawing a box to zoom in on the map will not work in combination with the ConstrainExtentBehavior. If ConstrainExtentBehavior is set, the tool will "jerk" the map, but never zooms, even though the zoomed geometry is well within the constraint. It will finally zoom after the 2nd or 3rd attempt.
As I workaround, I am setting the ConstrainExtentBehavior in code on UserControl_Loaded, removing it before I zoom, then replacing at the Map_ExtentChanged.   Am I missing something here?

System.Windows.Interactivity.Behavior behavior;

private void UserControl_Loaded(object sender, RoutedEventArgs e)
        {

            behavior = new ESRI.ArcGIS.Client.Behaviors.ConstrainExtentBehavior()
            {
                ConstrainedExtent = new ESRI.ArcGIS.Client.Geometry.Envelope(1116757.49248094, 183859.75, 1331330.81621366, 325602.25)
            };
            System.Windows.Interactivity.Interaction.GetBehaviors(MyMap).Add(behavior);

        }
private void myDrawObject_DrawComplete(object sender, DrawEventArgs args)
{

            switch (_toolMode)
            {
                case "zoomin":
                    System.Windows.Interactivity.Interaction.GetBehaviors(MyMap).Remove(behavior);
                    MyMap.ZoomTo(args.Geometry as ESRI.ArcGIS.Client.Geometry.Envelope);
                    break;
            }
}

private void MyMap_ExtentChanged(object sender, ExtentEventArgs e)
{
    if (System.Windows.Interactivity.Interaction.GetBehaviors(MyMap).Count == 0)
            {
                System.Windows.Interactivity.Interaction.GetBehaviors(MyMap).Add(behavior);
            }

}

Re: ConstrainExtentBehavior bug?

JenniferNery — Fri, 03 Dec 2010 16:19:35 GMT

I'm not able to replicate the issue when combining these two samples:

Zoom using Draw tool
http://help.arcgis.com/en/webapi/silverlight/samples/start.htm#ToolBarWidget

ConstrainExtentBehavior defined on XAML
http://help.arcgis.com/en/webapi/silverlight/samples/start.htm#ConstrainExtentBehavior

Re: ConstrainExtentBehavior bug?

MatthewLangley — Tue, 16 Aug 2011 23:21:01 GMT

I am seeing this same behaviour on the sample sites (and in my custom code). If I open the sample: http://help.arcgis.com/en/webapi/silverlight/samples/start.htm#ConstrainExtentBehavior and then zoom in (starting at full extent) the first 11 zoom attempts only zoom the map a very small amount. I then reach a point when the map zooms in correctly.

In my own code if I drag a zoom box on the map (with ConstrainExtentBehavior turned on in my XAML) the map does not zoom to the extent box - it only zooms in by a few percent. If I turn off the ConstrainExtentBehavior all zoom functions work as expected. I have tested in both Chrome and IE9, and this is happening on both browsers.

I am assuming others are seeing this issue as it can be reproduced on the ESRI samples.

Does anyone know of a suitable workaround, or if this has been logged as an official bug?

Re: ConstrainExtentBehavior bug?

NathanielWingfield — Fri, 19 Aug 2011 16:49:40 GMT

We experienced this too. It's clearly a bug.

Our needs were modest: we only wanted to constrain the extent of the "zoom to world" tool, so we just wrote our own implementation of the tool and removed the ConstrainExtentBehavior.