Difference Online

This sample demonstrates using an ESRI.ArcGIS.Client.Tasks GeometryService that takes an input polygon that cuts across another existing polygon graphic to return the different between the two polygons.

To use the sample, create a polygon on the map that intersects the existing graphic on the map (red). When complete the difference between the polygon and the original graphics will be displayed (yellow). Click the Reset button to remove the results.

XAML

<UserControl x:Class="ArcGISWPFSDK.Difference"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" 
    xmlns:esri="http://schemas.esri.com/arcgis/client/2009">
    <Grid x:Name="LayoutRoot" Background="White">
        <Grid.Resources>
            <esri:SimpleFillSymbol x:Key="DefaultFillSymbol" Fill="#88FF0000" BorderBrush="Red" />
            <esri:SimpleLineSymbol x:Key="DefaultLineSymbol" Color="Red" Width="2" />
            <esri:SimpleMarkerSymbol x:Key="DefaultMarkerSymbol" Color="Red" Size="8" />
            <esri:SimpleFillSymbol x:Key="DrawFillSymbol" Fill="#8800FFFF" BorderBrush="Cyan" />
            <esri:SimpleFillSymbol x:Key="DifferenceFillSymbol" Fill="#88FFFF00" BorderBrush="Yellow" />
            <LinearGradientBrush x:Key="PanelGradient" EndPoint="0.5,1" StartPoint="0.5,0">
                <LinearGradientBrush.RelativeTransform>
                    <TransformGroup>
                        <ScaleTransform CenterY="0.5" CenterX="0.5"/>
                        <SkewTransform CenterY="0.5" CenterX="0.5"/>
                        <RotateTransform Angle="176" CenterY="0.5" CenterX="0.5"/>
                        <TranslateTransform/>
                    </TransformGroup>
                </LinearGradientBrush.RelativeTransform>
                <GradientStop Color="#FF145787" Offset="0.16"/>
                <GradientStop Color="#FF3D7FAC" Offset="0.502"/>
                <GradientStop Color="#FF88C5EF" Offset="0.984"/>
            </LinearGradientBrush>
        </Grid.Resources>

        <esri:Map x:Name="MyMap" Extent="-117.5,32.5,-116.5,35.5">
            <esri:ArcGISTiledMapServiceLayer ID="StreetMapLayer" 
                                                 Url="http://services.arcgisonline.com/ArcGIS/rest/services/ESRI_StreetMap_World_2D/MapServer" />
            <esri:GraphicsLayer ID="InputGraphicsLayer">
                <esri:GraphicsLayer.Graphics >
                    <esri:Graphic Symbol="{StaticResource DefaultFillSymbol}">
                        <esri:Polygon>
                            <esri:Polygon.SpatialReference>
                                <esri:SpatialReference WKID="4326"/>
                            </esri:Polygon.SpatialReference>
                            <esri:Polygon.Rings>
                                <esri:PointCollection>-116.5,33 -116.5,34 -116,34 -116,33 -116.5,33</esri:PointCollection>
                            </esri:Polygon.Rings>
                        </esri:Polygon>
                    </esri:Graphic>
                    <esri:Graphic Symbol="{StaticResource DefaultFillSymbol}">
                        <esri:Polygon>
                            <esri:Polygon.SpatialReference>
                                <esri:SpatialReference WKID="4326"/>
                            </esri:Polygon.SpatialReference>
                            <esri:Polygon.Rings>
                                <esri:PointCollection>-118,34 -118,35 -117.5,35 -117.5,34 -118,34</esri:PointCollection>
                            </esri:Polygon.Rings>
                        </esri:Polygon>
                    </esri:Graphic>
                    <esri:Graphic Symbol="{StaticResource DefaultFillSymbol}">
                        <esri:Polygon>
                            <esri:Polygon.SpatialReference>
                                <esri:SpatialReference WKID="4326"/>
                            </esri:Polygon.SpatialReference>
                            <esri:Polygon.Rings>
                                <esri:PointCollection>-117.3,34 -116.3,34 -116.3,33.5 -117.3,33.5 -117.3,34</esri:PointCollection>
                            </esri:Polygon.Rings>
                        </esri:Polygon>
                    </esri:Graphic>
                </esri:GraphicsLayer.Graphics>
            </esri:GraphicsLayer>
            <esri:GraphicsLayer ID="OutputGraphicsLayer" />
        </esri:Map>

        <Grid HorizontalAlignment="Right" VerticalAlignment="Top" Margin="0,10,10,0" >
            <Rectangle Fill="{StaticResource PanelGradient}" Stroke="Gray"  RadiusX="10" RadiusY="10" Margin="0,0,0,5" >
                <Rectangle.Effect>
                    <DropShadowEffect/>
                </Rectangle.Effect>
            </Rectangle>
            <Rectangle Fill="#FFFFFFFF" Stroke="DarkGray" RadiusX="5" RadiusY="5" Margin="10,10,10,15" />
            <StackPanel Orientation="Vertical" Margin="30,20,20,30" >
                <TextBlock x:Name="ResponseTextBlock" Text="Create a polygon on the map that intersects the existing graphic on the map (red). When complete the difference between the polygon and the original graphics will be displayed (yellow).  Click the Reset button to remove the results."  
                           Width="400" TextAlignment="Left"  TextWrapping="Wrap" Foreground="Black"/>
                <Button Content="Reset" Margin="0,5,5,0" x:Name="ResetButton" 
                             Click="ResetButton_Click" IsEnabled="False" Width="150" />
            </StackPanel>
        </Grid>
    </Grid>
</UserControl>

C#

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Animation;
using ESRI.ArcGIS.Client;
using ESRI.ArcGIS.Client.Tasks;
using ESRI.ArcGIS.Client.Geometry;

namespace ArcGISWPFSDK
{
    public partial class Difference : UserControl
    {
        private Draw MyDrawObject;
        GeometryService geometryService;
        GraphicsLayer inputGraphicsLayer;
        GraphicsLayer outputGraphicsLayer;

        public Difference()
        {
            InitializeComponent();

            geometryService =
                        new GeometryService("http://tasks.arcgisonline.com/ArcGIS/rest/services/Geometry/GeometryServer");

            geometryService.DifferenceCompleted += GeometryService_DifferenceCompleted;
            geometryService.SimplifyCompleted += GeometryService_SimplifyCompleted;
            geometryService.Failed += GeometryService_Failed;

            inputGraphicsLayer = MyMap.Layers["InputGraphicsLayer"] as GraphicsLayer;

            MyDrawObject = new Draw(MyMap)
                {
                    DrawMode = DrawMode.Polygon,
                    IsEnabled = true,
                    FillSymbol = LayoutRoot.Resources["DrawFillSymbol"] as ESRI.ArcGIS.Client.Symbols.FillSymbol
                };
            MyDrawObject.DrawComplete += MyDrawObject_DrawComplete;
        }

        private void MyDrawObject_DrawComplete(object sender, DrawEventArgs args)
        {
            MyDrawObject.IsEnabled = false;

            ESRI.ArcGIS.Client.Geometry.Polygon polygon = args.Geometry as ESRI.ArcGIS.Client.Geometry.Polygon;
            polygon.SpatialReference = MyMap.SpatialReference;

            geometryService.SimplifyAsync(new List<Graphic>() { new Graphic() { Geometry = polygon } });
        }

        void GeometryService_SimplifyCompleted(object sender, GraphicsEventArgs e)
        {
            geometryService.DifferenceAsync(inputGraphicsLayer.Graphics.ToList(), e.Results[0].Geometry);
        }

        void GeometryService_DifferenceCompleted(object sender, GraphicsEventArgs e)
        {
            outputGraphicsLayer = MyMap.Layers["OutputGraphicsLayer"] as GraphicsLayer;
            outputGraphicsLayer.ClearGraphics();
            foreach (Graphic g in e.Results)
            {
                if (g.Geometry is Polygon)
                    g.Symbol = LayoutRoot.Resources["DifferenceFillSymbol"] as ESRI.ArcGIS.Client.Symbols.Symbol;
                outputGraphicsLayer.Graphics.Add(g);
            }

            MyDrawObject.IsEnabled = true;
            ResetButton.IsEnabled = true;
        }

        private void GeometryService_Failed(object sender, TaskFailedEventArgs e)
        {
            MessageBox.Show("Geometry Service error: " + e.Error);
            MyDrawObject.IsEnabled = true;
        }

        private void ResetButton_Click(object sender, RoutedEventArgs e)
        {
            GraphicsLayer outputGraphicsLayer = MyMap.Layers["OutputGraphicsLayer"] as GraphicsLayer;
            outputGraphicsLayer.ClearGraphics();

            ResetButton.IsEnabled = false;
        }
    }
}

VB.NET

Imports System.Collections.Generic
Imports System.Linq
Imports System.Net
Imports System.Windows
Imports System.Windows.Controls
Imports System.Windows.Documents
Imports System.Windows.Input
Imports System.Windows.Media
Imports System.Windows.Media.Animation
Imports ESRI.ArcGIS.Client
Imports ESRI.ArcGIS.Client.Tasks
Imports ESRI.ArcGIS.Client.Geometry

Namespace ArcGISWPFSDK
    Partial Public Class Difference
        Inherits UserControl
        Private MyDrawObject As Draw
        Private geometryService As GeometryService
        Private inputGraphicsLayer As GraphicsLayer
        Private outputGraphicsLayer As GraphicsLayer

        Public Sub New()
            InitializeComponent()

            geometryService = New GeometryService("http://tasks.arcgisonline.com/ArcGIS/rest/services/Geometry/GeometryServer")

            AddHandler geometryService.DifferenceCompleted, AddressOf GeometryService_DifferenceCompleted
            AddHandler geometryService.SimplifyCompleted, AddressOf GeometryService_SimplifyCompleted
            AddHandler geometryService.Failed, AddressOf GeometryService_Failed

            inputGraphicsLayer = TryCast(MyMap.Layers("InputGraphicsLayer"), GraphicsLayer)

            MyDrawObject = New Draw(MyMap) With { _
             .DrawMode = DrawMode.Polygon, _
             .IsEnabled = True, _
             .FillSymbol = TryCast(LayoutRoot.Resources("DrawFillSymbol"), ESRI.ArcGIS.Client.Symbols.FillSymbol) _
            }
            AddHandler MyDrawObject.DrawComplete, AddressOf MyDrawObject_DrawComplete
        End Sub

        Private Sub MyDrawObject_DrawComplete(sender As Object, args As DrawEventArgs)
            MyDrawObject.IsEnabled = False

            Dim polygon As ESRI.ArcGIS.Client.Geometry.Polygon = TryCast(args.Geometry, ESRI.ArcGIS.Client.Geometry.Polygon)
            polygon.SpatialReference = MyMap.SpatialReference

            geometryService.SimplifyAsync(New List(Of Graphic)() From { _
             New Graphic() With { _
              .Geometry = polygon _
             } _
            })
        End Sub

        Private Sub GeometryService_SimplifyCompleted(sender As Object, e As GraphicsEventArgs)
            geometryService.DifferenceAsync(inputGraphicsLayer.Graphics.ToList(), e.Results(0).Geometry)
        End Sub

        Private Sub GeometryService_DifferenceCompleted(sender As Object, e As GraphicsEventArgs)
            outputGraphicsLayer = TryCast(MyMap.Layers("OutputGraphicsLayer"), GraphicsLayer)
            outputGraphicsLayer.ClearGraphics()
            For Each g As Graphic In e.Results
                If TypeOf g.Geometry Is Polygon Then
                    g.Symbol = TryCast(LayoutRoot.Resources("DifferenceFillSymbol"), ESRI.ArcGIS.Client.Symbols.Symbol)
                End If
                outputGraphicsLayer.Graphics.Add(g)
            Next

            MyDrawObject.IsEnabled = True
            ResetButton.IsEnabled = True
        End Sub

        Private Sub GeometryService_Failed(sender As Object, e As TaskFailedEventArgs)
            MessageBox.Show("Geometry Service error: " & Convert.ToString(e.[Error]))
            MyDrawObject.IsEnabled = True
        End Sub

        Private Sub ResetButton_Click(sender As Object, e As RoutedEventArgs)
            Dim outputGraphicsLayer As GraphicsLayer = TryCast(MyMap.Layers("OutputGraphicsLayer"), GraphicsLayer)
            outputGraphicsLayer.ClearGraphics()

            ResetButton.IsEnabled = False
        End Sub
    End Class
End Namespace