How to change a layer property with C# code?

Anonymous User

Original User: huangs3

Hi Experts:

    I am using the Silverlight/WPF API to implement a magnifying glass on a map.
    Attached pictures are the XAML code and C# code I am using.
    The C# code (shown in errNewTiledMapServiceLyr.png file) tries to dynamically change the Layer property of the magnifying glass, but it failed. From the error message, seems it is because of unapporiate initialization of ArcGISTiledMapServiceLayer object. However, I follows the method in http://help.arcgis.com/en/webapi/silverlight/samples/start.htm#AddLayerDynamically
and I couldn't find out how I should fix it.
    Can you give me some suggestion?
    Thank you.

errNewTiledMapServiceLyr.png

xamlCode.png

Anonymous User

Original User: huangs3

Hi Jenniferdnery:

    Thank you for your test.
    I re-checked my code and found that the issue happens at program startup because at that time the MagnifyingGlass object is not initialized yet.
    I changed the event handler to the following and it works:

*************************************
private void RadioButton_Checked(object sender, RoutedEventArgs e)
{
   if (MagnifyingGlass != null)
   {
        ArcGISTiledMapServiceLayer newMagnifyingGlassLayer = new ArcGISTiledMapServiceLayer();
        newMagnifyingGlassLayer.Url = "http://xyz";
        MagnifyingGlass.Layer = newMagnifyingGlassLayer;
    }
}
**************************************