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UniqueValueRenderer change polygon fill color dynamically

xariaD

How to change the fill color of a particular polygon at runtime?

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IkaRasidina

I got it working, not by using UniqueValueRenderer though.

Hi Xaria,

I also want to change polygon fill color dynamically, but I'm new in SL API Programming. Can you give the source code of simple example to me? coz i'm blind with this one.

Thank You.

xariaD

I got it working, not by using UniqueValueRenderer though.

JenniferNery

It might be because sampleserver3 gets refreshed every night. You can try to add features of these feature types first and then use the unique value renderer and this code.

xariaD

Hi Jennifer,

I used your code, and I cannot see the feature layer at all.

JenniferNery

I tried this sample in both WPF and SL application. I placed debug break points to the EndSaveEdits and SaveEditsFailed too. It would help to familiarize yourself with the feature layer first, it's field names and expected values. http://sampleserver3.arcgisonline.com/ArcGIS/rest/services/BloomfieldHillsMichigan/LandusePlanning/FeatureServer/2

XAML-code:

  <UserControl.Resources>
        <esri:SimpleFillSymbol x:Key="MyYellowFillSymbol"
                                      Fill="YellowGreen"
                                      BorderBrush="Transparent"
                                      BorderThickness="2" />
        <esri:SimpleFillSymbol x:Key="MyRedFillSymbol"
                                      Fill="Red"
                                      BorderBrush="Transparent"
                                      BorderThickness="2" />
        <esri:UniqueValueRenderer x:Key="MyUniqueValueRenderer"
                                  Attribute="symbolname">
            <esri:UniqueValueRenderer.Infos>
                <esri:UniqueValueInfo Value="Residential - Very Low Density"
                                      Symbol="{StaticResource MyRedFillSymbol}" />
                <esri:UniqueValueInfo Value="Residential - Low Density"
                                      Symbol="{StaticResource MyYellowFillSymbol}" />
            </esri:UniqueValueRenderer.Infos>
        </esri:UniqueValueRenderer>
    </UserControl.Resources>
    <Grid x:Name="LayoutRoot" Background="White">
        <esri:Map x:Name="MyMap">
            <esri:ArcGISTiledMapServiceLayer Url="http://server.arcgisonline.com/ArcGIS/rest/services/World_Street_Map/MapServer" />
            <esri:FeatureLayer ID="towers"
                               Url="http://sampleserver3.arcgisonline.com/ArcGIS/rest/services/BloomfieldHillsMichigan/LandusePlanning/FeatureServer/2"
                               Where="1=1"
                               Renderer="{StaticResource MyUniqueValueRenderer}"                     
                               EndSaveEdits="FeatureLayer_EndSaveEdits"
                               SaveEditsFailed="FeatureLayer_SaveEditsFailed"
                               MouseLeftButtonDown="FeatureLayer_MouseLeftButtonDown">
                <esri:FeatureLayer.OutFields>
                    <sys:String>symbolname</sys:String>
                </esri:FeatureLayer.OutFields>
            </esri:FeatureLayer>
        </esri:Map>
</Grid>

Code-Behind:

        private void FeatureLayer_MouseLeftButtonDown(object sender, ESRI.ArcGIS.Client.GraphicMouseButtonEventArgs e)
        {
            Graphic g = e.Graphic;
            string currentValue = (string) g.Attributes["symbolname"];
            if(currentValue.Contains("Very"))
                g.Attributes["symbolname"] = "Residential - Low Density";
            else
                g.Attributes["symbolname"] = "Residential - Very Low Density";
        }

        private void FeatureLayer_EndSaveEdits(object sender, ESRI.ArcGIS.Client.Tasks.EndEditEventArgs e)
        {

        }

        private void FeatureLayer_SaveEditsFailed(object sender, ESRI.ArcGIS.Client.Tasks.TaskFailedEventArgs e)
        {

        }

Jennifer

xariaD

You can also listen to EndSaveEdits and SaveEditsFailed to see if a graphic is updated.

The EndSaveEdits or SaveEditsfailed is never triggered!!!
So I added a BeginSaveEdits and that is not triggered either 😞
What is wrong here???

xariaD

Jennifer,
Are you using WPF or Silverlight?

I do not see the color change at all. The graphic is updated,I included a Maptip and I can see the change in attribute value when I mouse over the graphic, after Mouse Click.

Could you please post your code so that I can see if it works in my application.

JenniferNery

Hi Xaria,

I tried to replicate the issue using your code with minor tweaks.
Changes to FeatureLayer:
Url="http://sampleserver3.arcgisonline.com/ArcGIS/rest/services/BloomfieldHillsMichigan/LandusePlanning/FeatureServer/2"
OutFields="symbolname."
Changes to UniqueValueRenderer:
Attribute="symbolname"
Changed Value property of each UniqueValueInfo to code values the FeatureServer expects (see FeatureLayer's Url)
      <esri:UniqueValueInfo Value="Residential - Very Low Density"
                                    Symbol="{StaticResource MyRedFillSymbol}" />
      <esri:UniqueValueInfo Value="Residential - Low Density"
                                    Symbol="{StaticResource MyYellowFillSymbol}" />
            </esri:UniqueValueRenderer.Infos>
In the code-behind (FeatureLayer_MouseLeftButtonDown)
Graphic g = e.Graphic;
g.Attributes["symbolname"] = "Residential - Very Low Density";

As soon as the symbolname attribute is changed, I see the graphic's fill color change from Yellow to Red if I clicked on a graphic that had Yellow/"Residential - Low Density".

The only difference from your code is that you were using Url="http://MyMapURL/MapServer/0 (A MapServer). I also tried using MapServer and the fill color would still change dynamically after changing the attribute, but ofcourse on page refresh or application restart, the graphic changes back to its original color because the FeatureLayer is read-only. Do you not see the color change at all?

It seems there's no problem with your code. The Attribute property of the UniqueValueRenderer must match a field in the FeatureServer and the Value property of each UniqueValueRender.Info must be a type/value that field accepts.

You can also listen to EndSaveEdits and SaveEditsFailed to see if a graphic is updated.

Jennifer

xariaD

Is there something I need to check on the server? Some setting on the publishing side?

xariaD

Yeah It does get executed, and the attribute is assigned as well, but the color does not change.

I am using ver 2.0

Bud_0-1776965258817.png

DominiqueBroux

I tested with your code and I didn't get any problem.
So I don't understand

I guess you have verified that your event handler 'FeatureLayer_MouseLeftButtonDown' is executed?

Which ArcGIS SL API version are you using?

xariaD

 private void FeatureLayer_MouseLeftButtonDown(object sender, GraphicMouseButtonEventArgs e)
        {
            Graphic feature = e.Graphic;          
            feature.Attributes["Status"] = "On";
        }

This is what I have in code behind.
What to do??

xariaD

No, that is not the case either.
The status is defined as String "On"/"Off" and I am assigning the same in code behind.
😞

DominiqueBroux

Might be that the status is initialized with coded values such as 0 and 1 and your renderer is using strings "On"/"Off".

xariaD

NOoooooooooooooooooooooooooo

I know it is case-sensitive, and I am using "Status" in code behind.

DominiqueBroux

So when I set the graphic.Attributes["status"] to newstatus value, it is not rendered.

<esri:UniqueValueRenderer x:Key="MyUniqueValueRenderer" Attribute="Status" >

Looks like you are using status in code and Status in XAML.
Attribute names are case sensitive.

xariaD

 <esriSymbols:SimpleFillSymbol x:Key="MyYellowFillSymbol" Fill="YellowGreen" BorderBrush="Transparent" BorderThickness="2" />
            <esriSymbols:SimpleFillSymbol x:Key="MyRedFillSymbol" Fill="Red" BorderBrush="Transparent" BorderThickness="2" />
            <esri:UniqueValueRenderer x:Key="MyUniqueValueRenderer" Attribute="Status" >
                <esri:UniqueValueRenderer.Infos>
                    <esri:UniqueValueInfo Value="Off" Symbol="{StaticResource MyRedFillSymbol}" />
                    <esri:UniqueValueInfo Value="On" Symbol="{StaticResource MyYellowFillSymbol}"/>                    
                </esri:UniqueValueRenderer.Infos>
            </esri:UniqueValueRenderer>

And the feature layer is

<esri:FeatureLayer ID="towers" Url="http://MyMapURL/MapServer/0"
       Where="1=1" Renderer="{StaticResource MyUniqueValueRenderer}"
        MouseLeftButtonDown="FeatureLayer_MouseLeftButtonDown">
 <esri:FeatureLayer.OutFields>
         <sys:String>RefName</sys:String>
         <sys:String>Status</sys:String>
         <sys:String>Text</sys:String>
 </esri:FeatureLayer.OutFields>
</esri:FeatureLayer>

DominiqueBroux

It should be automatic when you change the value of an attribute which is used in the renderer.

How looks your renderer which is using the attribute 'status'?

xariaD

But I still don't understand how to dynamically apply the renderer.
The status of all graphic when the map is loaded is 0.
The status changes after the application starts.
So when I set the graphic.Attributes["status"] to newstatus value, it is not rendered.
How to refresh renderer or apply new renderer?

xariaD

Did you set the OutFields property on the FeatureLayer?

Yeah I missed that.

SomeGISGuy

Did you set the OutFields property on the FeatureLayer?

xariaD

I have added attributes to the map in ArcMap, and the REST service also displays all the attributes as fields. The web application displays all attributes in the identify table.

But WPF Application does not display those attributes. WHAT could be the reason? What should I check please guide me.

xariaD

The attributes are not displayed in the WPF application.
I have attributes like ObjectId, RefName, text, txtMemo, status
but the feature layer has attribute
RefName, Shape_Length and Shape_area
😞

Ans as usual the web application is showing the attributes under the identify feature correctly!!!!!
:mad:

xariaD

Yes, it's the easiest way.

You can add attributes at runtime :

 
if (graphic.Attributes.ContainsKey("Status"))
  graphic.Attributes["Status"] = status;
else
  graphic.Attributes.Add("Status", status);

When should the attribute be added? During layer Initialization? Or do I need to add a task?

DominiqueBroux

So does that mean Status should be defined as an attribute of the feature?

Yes, it's the easiest way.

But the status changes dynamically, and the status is passed to the WPF application via WCF operation.
So how to assign the new attribute value?

You can add attributes at runtime :

 
if (graphic.Attributes.ContainsKey("Status"))
  graphic.Attributes["Status"] = status;
else
  graphic.Attributes.Add("Status", status);

xariaD

So does that mean Status should be defined as an attribute of the feature?

But the status changes dynamically, and the status is passed to the WPF application via WCF operation.
So how to assign the new attribute value?

DominiqueBroux

Looks like a standard usage of an UniqueValueRenderer.

Create two symbols (in your resources), one green and one red.
In your UniqueValueRenderer, affect the red symbol to value 0 and the green one to value 1.

The symbol will automatically change when the status value changes.

See sample http://help.arcgis.com/en/webapi/silverlight/samples/start.htm#RenderersXAML

age-of-moon.jpg

xariaD

My problem lies in retrieving the polygon from feature layer.
The feature layer has multiple polygons. Also, I have a table stored in SQL database which stores status values of these polygons.
When the status changes the color should change.
So suppose if for polygon 1 status is 1 color is green,
then when the status for polygon changes to 0 the color should be red.

How do I apply the color change to polygon 1wiithout changing the color of other polygons?

DominiqueBroux

This thread http://forums.arcgis.com/threads/6481-Dynamically-change-color-of-a-symbol?highlight=symbol+binding could help (by replacing markersymbol by fillsymbol).

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