Layer Definition

Question

I am playing around with Layer Definitions for a ArcGISDynamicMapService. I have never done this before and I am stuck. When I run this nothing happens in my map. It seems like after it hits the  dynamicServiceLayer.LayerDefinitions.Add(lDef); line it just stops without warning. I places a messagebox right after this line and it never shows. Any ideas? Thanks..
string myLayer = "PoliciesSDE";
            ArcGISDynamicMapServiceLayer dynamicServiceLayer = MapApplication.Current.Map.Layers[myLayer] as ArcGISDynamicMapServiceLayer;            
            LayerDefinition lDef = new LayerDefinition();
            lDef.LayerID = 0;           
            lDef.Definition = "State = 'OREGON'";
            dynamicServiceLayer.LayerDefinitions.Add(lDef);
            dynamicServiceLayer.Refresh();

BrianLeroux · Answer

I managed to get this to work. Iterating through the layers was the only way I could come up with to find the layer I wanted based on Layer Name. If anyone has a better way please let me know. string strState = cmbState.SelectionBoxItem.ToString().ToUpper(); string strlDef = "State = '" + strState + "'"; foreach (Layer myLayer in MapApplication.Current.Map.Layers) { strLayerName = MapApplication.GetLayerName(myLayer); if (strLayerName == "PoliciesSDE") { string layerID = myLayer.ID; LayerDefinition lDef = new LayerDefinition(); lDef.LayerID = 0; lDef.Definition = strlDef; // Create an ObservableCollection and add the .Definition to it. System.Collections.ObjectModel.ObservableCollection myObservableCollection2 = new System.Collections.ObjectModel.ObservableCollection(); myObservableCollection2.Add(lDef); ArcGISDynamicMapServiceLayer dynamicServiceLayer = MapApplication.Current.Map.Layers[layerID] as ArcGISDynamicMapServiceLayer; dynamicServiceLayer.LayerDefinitions = (myObservableCollection2); dynamicServiceLayer.Refresh(); } }

BrianLeroux · Answer

So I changed the following line to use the Layers index number and now it works fine. 
ArcGISDynamicMapServiceLayer dynamicServiceLayer = MapApplication.Current.Map.Layers[7] as ArcGISDynamicMapServiceLayer

Unfortunately this will not work for me as users have the ability to move layers in the map. I will also not be able to use the layers ID either because when I add the layer to the map using the Builder App it adds a ID like b47f9704b58b4aa6b77c93cf9faaf8f2 which varies from map to map when adding the same layer. I want my tool to go after the same layer in various map applications so I will not be able to use the layer ID as they will be different in every one.

The layer I want to add a definition to will always have the same name but I can't figure out how to reference a layer by name. Has anyone been able to do this?

BrianLeroux · Answer

This does not work eaither but is based on the sample in the Silverlight API Reference. string myLayer = "PoliciesSDE"; ArcGISDynamicMapServiceLayer dynamicServiceLayer = MapApplication.Current.Map.Layers[myLayer] as ArcGISDynamicMapServiceLayer; LayerDefinition lDef = new LayerDefinition(); lDef.LayerID = 0; lDef.Definition = "State = 'OREGON'"; // Create an ObservableCollection and add the .Definition to it. System.Collections.ObjectModel.ObservableCollection myObservableCollection2 = new System.Collections.ObjectModel.ObservableCollection(); myObservableCollection2.Add(lDef); MessageBox.Show("Collection made."); dynamicServiceLayer.LayerDefinitions = (myObservableCollection2); MessageBox.Show("Definition Applied."); dynamicServiceLayer.Refresh();