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featuredatagrid and binding with graphicslayers &amp; featurelayers

MichaelBlom

Hi there,

I'm creating a featuredatagrid that I want to link with my map (select grid, map graphic selected and vice versa a la this example: http://help.arcgis.com/en/webapi/silverlight/samples/start.htm#FeatureDataGrid)

but I need my featuredatagrid to reference a GraphicsLayer, not a FeatureLayer

...I create my GraphicsLayer in the xaml:
<esri:GraphicsLayer ID="StormRegions"/>

...do the binding in the xaml:
<esri:FeatureDataGrid Grid.Row="2" x:Name="stormsDataGrid" Visibility="Visible"
Map="{Binding ElementName=RiskMap}"
GraphicsLayer="{Binding ElementName=RiskMap, Path=Layers.[StormRegions]}"

...and then reference in my code behind:
stormPolys = RiskMap.Layers["StormRegions"] as GraphicsLayer;

...and then populate the GraphicsLayer:
stormPolys.Graphics.Insert(0, feature);

The problem is, in binding a GraphicsLayer, I don't seem to get the same kind of map-datagrid-selection-interaction that binding a FeatureLayer to a FeatureDataGrid seems to acheive.

Has anyone managed to achieve this someone?

Thanks in Advance,
Mike

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stefanschlaefli

I use a Classbreak renderer on my featurelayer. The featurelayer is bound to the featuredatagrid. More or less like in example http://help.arcgis.com/en/webapi/silverlight/samples/start.htm#FeatureDataGrid When I do it like this, I then only see the graphicslayer (all features with the same symbol, except the selected one) but not anymore the featurelayer with it's classbreakrenderer. I also tried with Ali's example (transparent symbology with blue border of the selected object), but then also, I only see the selected graphics of the graphic layer, but not the featurelayer class breaks. How would you do that to combine a classbreakrenderer and a featuredatagrid? Would you add the same featurelayer twice and bind the featuredatagrid to one of them? Or would I have to add the controltemplate by code when i generate the class breaks? Thanks for any suggestions.

AliMirzabeigi

Here is a sample:

<esri:Map x:Name="MyMap">
            <esri:Map.Extent>
                <esri:Envelope XMin="661140" YMin="-1420246" XMax="3015668" YMax="1594451" >
                    <esri:Envelope.SpatialReference>
                        <esri:SpatialReference WKID="26777"/>
                    </esri:Envelope.SpatialReference>
                </esri:Envelope>
            </esri:Map.Extent>
            <!-- Layer definitions here -->
</esri:Map>

MichaelBlom

Thanks Ali,

what does this look like in code: "envelope that has a SpatialReference defined"?

because I thought envelope just allows you to define a north,east, south, west but not a spatial reference.

Thanks,
Mike

AliMirzabeigi

Hello Mike,

I'm glad that you figured out the problem! Just for your reference I'm adding a quote from ESRI API reference in regards to this issue:

Spatial Reference: The Map's spatial reference is determined by the first layer in the map that has this property set. However, it can be overridden by explicitly setting the Extent property with an envelope that has a SpatialReference defined. This has to be done before any layers will be initalized by the map. Once the spatial reference of a map has been set and the layers has loaded, the spatial reference can no longer be changed. If you need to change spatial reference on the fly, you can instead create a new map instance, move the layers to this map, and replace the previous map instance. Also note that tiled layers does not support reprojection, and will not be displayed if the Map's SpatialReference does not match the spatial reference of the tiled layer.

MichaelBlom

Hi Ali,

You've pointed me in the right direction.

My problem was that the base layer which I was using was in WGS84 projection (ESRI_StreetMap_World_2D,4326) and my service was in web mercator (102113).

When I switched my base map to Worrld_Street_Map (Web Mercator Auxilary - 10211), the graphics rendered.

It's a bit odd that my dynamicMapServiceLayer will render over the WGS84 Map, but create a graphicsLayer from this dynamicService and the graphics won't renender.

Anyhow, your transparent symbology xaml code works a treat!

Thanks again.
Mike

AliMirzabeigi

It could also be the case that the spatial reference of your map doesn't match the spatial reference of your GraphicsLayer. You can explicitly set the spatial reference of your map control by defining an extent with an envelope in which its spatial reference is explicitly defined (if you're doing this in the code-behind make sure it's done before any of your layers getting initialized).

MichaelBlom

Browsing to the layer in my service, the SHAPE field exists.

Debugging features from the service in .net, geometery is defined (web mercator), extent is defined... see image attached.

Does anything look suspect in here to you?

polygonObject.JPG

AliMirzabeigi

Have you verified whether graphic collection in your feature set have their geometry set? If that's the case then you have issues in your service. I would also suggest to check whether there is an extent associated with each graphic returned by your service as they may have NULL extents (another possible issue).

MichaelBlom

Thanks for your code Ali, its very elegant... but it doesn't seem to work in my case here.

I got to looking at the features I add into my GraphicsLayer, these features are the results of a querytask where my query does include ReturnGeometry = true.

foreach (var feature in stormPolygons.FeatureSet.Features)
            {
                foreach(var att in feature.Attributes)
                {
                    string keyvalue = att.Key.ToString();
                }

I itterated through the attributes, and I have a Shape_Length attribute, and a Shape_Area attribute, but no traditional seen SHAPE attribute.

Could this be an issue?

AliMirzabeigi

Mike,

For GraphicsLayer you need to either define a Renderer to be used by all features in your layer or set the Symbol property of each layer while adding them to your layer. To use the first approach (Renderer with a transparent symbology in which gets a blue border when the graphic element gets selected) you can use the following resource in your XAML:

            <esri:SimpleFillSymbol x:Key="TransparentFillSymbol">
                <esri:SimpleFillSymbol.ControlTemplate>
                    <ControlTemplate>
                        <Path x:Name="Element" Fill="Transparent" Stroke="Transparent" StrokeThickness="1">
                            <VisualStateManager.VisualStateGroups>
                                <VisualStateGroup x:Name="SelectionStates">
                                    <VisualState x:Name="Unselected">
                                        <Storyboard>
                                            <ColorAnimation Storyboard.TargetName="Element"
                                                            Storyboard.TargetProperty="(Path.Stroke).(SolidColorBrush.Color)" 
                                                            To="Transparent" Duration="0:0:0.5" />
                                        </Storyboard>
                                    </VisualState>
                                    <VisualState x:Name="Selected">
                                        <Storyboard>
                                            <ColorAnimation Storyboard.TargetName="Element"
                                                            Storyboard.TargetProperty="(Path.Stroke).(SolidColorBrush.Color)" 
                                                            To="Blue" Duration="0:0:0.5" />
                                        </Storyboard>
                                    </VisualState>
                                </VisualStateGroup>
                            </VisualStateManager.VisualStateGroups>
                        </Path>
                    </ControlTemplate>
                </esri:SimpleFillSymbol.ControlTemplate>
            </esri:SimpleFillSymbol>

Then define a Renderer like the following code snippet:

<esri:SimpleRenderer x:Key="TransparentRenderer" Symbol="{StaticResource TransparentFillSymbol}" />

And finally, define your GraphicsLayer like below in your map layers collection:

<esri:GraphicsLayer ID="MyGraphicsLayer" Renderer="{StaticResource TransparentRenderer}" />

Doing this way you won't need to set the symbol property of each graphic object while adding them into your GraphicsLayer.

DominiqueBroux

Might be a geometry type issue.

FillSymbols are working with polygon geometry.
What is the geometry type of your graphics? How do you initialize it?

MichaelBlom

Ok, I've found this.

"A set of new symbol renderers are available for graphics and feature layers:
SimpleRenderer - Used to define a single symbol to render features in a graphics or feature layer. Enables the ability to define a single symbol in XAML with which to render graphics in a graphic layer. While this was possible for feature layer using the FeatureSymbol property, this provides a single standard pattern for all graphics layers and derivatives. "

Perfect, exactly what i'm looking for:

<Grid.Resources>
         <esriSymbols:SimpleFillSymbol x:Key="ClearFill" Fill="#66FF0000" BorderBrush="Red" BorderThickness="2"/>
            <esri:SimpleRenderer x:Key="MySimpleRenderer" Symbol="{StaticResource ClearFill}">
            </esri:SimpleRenderer>
        </Grid.Resources>
....
<esri:GraphicsLayer ID="StormRegions" Renderer="{StaticResource MySimpleRenderer}" Visible="True" />
...

But my graphics still are not showing up on my map... I'm going crazy.

I've also tried to apply the renderer in the code behind:

stormPolys.Renderer = MySimpleRenderer;

Nothing....

MichaelBlom

Thank you both.

I don't actually need to set breaks, define bins and all that stuff that goes with renderers.

I'd like to just apply a simplefillsymbol to my graphicslayer. A transparent one actually, so that all i see is the blue "selected" border when i click on the record in my datagrid. The layer is already "on" the map via a dynamic map service.

Is it the case that I must define a renderer in order to display a graphics layer?

It looks like a featurelayer you can just apply a simplefillsymbol, but not a graphicslayer.

Thanks again,
Mike

oh, i also tried in code behind, but graphicslayer is still not showing on my map.

SimpleFillSymbol fillSymbol = new SimpleFillSymbol()
                {
                    BorderBrush = new SolidColorBrush(Color.FromArgb(0, 255, 0, 0)),
                    BorderThickness = 2,
                    Fill = new SolidColorBrush(Color.FromArgb(0, 255, 0, 0))
                };

foreach (var f in stormPolys.Graphics)
                    f.Symbol = fillSymbol;
stormPolys.Refresh();

JenniferNery

Yup. Ali is right, no graphics can be clicked because there's no symbol for it. You can set GraphicsLayer.Renderer in XAML. It shouldn't be any different than how FeatureLayer.Renderer is set so you can refer to these sample: http://help.arcgis.com/en/webapi/silverlight/samples/start.htm#FeatureLayerRendering You can simply use SimpleRenderer with the appropriate symbol template for your geometry type.

Jennifer

AliMirzabeigi

If you cannot see your graphics on the map then it seems that you haven't defined the "Symbol" property of your GraphicsLayer.

MichaelBlom

Hi Jennifer,

Thank-you for your reply.

My Graphics do include attributes (including shape) and the Binding is working between the GraphicsLayer and the FeatureDataGrid, all the attributes are displayed.

My Graphics don't show on my Map though.

MouseLeftDown on the grid does nothing, but this might be because I can't see the graphics on my map (am I right to say that clicking on the datagrid row should inherently select the graphic on the map without adding any code behind?)

Thanks,
Mike

JenniferNery

The Binding looks correct and it should work.

Do your Graphics include Attributes? The Attributes will define the field names for the FeatureDataGrid. Do you show the rows and columns?

What does your FeatureDataGrid display on GraphicsLayer MouseLeftButtonDown?

Jennifer

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