Query with a Buffer Online

This sample demonstrates using a geometry service to generate query geometry. To use the sample, simply click on the map. The click point will be buffered and parcels that intersect the buffer will be retrieved and drawn.

In the code-behind, a GeometryService is used to generate the buffer from the click point. A QueryTask is then used to perform a query using the buffer geometry.

XAML

<UserControl x:Class="ArcGISWPFSDK.BufferQuery"
    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:PictureMarkerSymbol x:Key="DefaultMarkerSymbol" OffsetX="11" OffsetY="39" Source="/Assets/Images/i_pushpin.png" />
            <esri:SimpleFillSymbol x:Key="BufferSymbol" Fill="#66BB0000" BorderBrush="#88CC0000" BorderThickness="2"  />
            <esri:SimpleFillSymbol x:Key="ParcelSymbol" Fill="#440000FF" BorderBrush="Blue" BorderThickness="2" />
            <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" Background="White" WrapAround="True"
                  Extent="-9270434.248,5246977.326,-9269261.417,5247569.712" 
                  MouseClick="MyMap_MouseClick">
            <esri:ArcGISTiledMapServiceLayer ID="StreetMapLayer" 
                      Url="http://services.arcgisonline.com/ArcGIS/rest/services/World_Street_Map/MapServer" />
            <esri:GraphicsLayer ID="MyResultsGraphicsLayer">
                <esri:GraphicsLayer.MapTip>
                    <Border BorderBrush="DarkGray" Background="Azure" CornerRadius="3" BorderThickness="1" Padding="3">
                        <StackPanel Orientation="Vertical">
                            <TextBlock Text="Owner:" FontWeight="Bold" HorizontalAlignment="Left" VerticalAlignment="Center" Foreground="Black"  />
                            <TextBlock Text="{Binding [OWNERNME1]}" HorizontalAlignment="Left" VerticalAlignment="Center" Foreground="Black"  />
                        </StackPanel>
                    </Border>
                </esri:GraphicsLayer.MapTip>
            </esri:GraphicsLayer>
            <esri:GraphicsLayer ID="MyGraphicsLayer" IsHitTestVisible="False"/>
        </esri:Map>

        <Grid HorizontalAlignment="Right" VerticalAlignment="Top" Margin="0,15,15,0" >
            <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" />
            <TextBlock x:Name="InformationTextBlock" 
                 Text="Click on map to set a location. A buffer will used to display parcels within 100 meters of the location." 
                 Width="200" Margin="30,20,30,25" HorizontalAlignment="Left" TextWrapping="Wrap" Foreground="Black" />
        </Grid>

    </Grid>
</UserControl>

C#

using System.Windows;
using System.Windows.Controls;
using ESRI.ArcGIS.Client;
using ESRI.ArcGIS.Client.Geometry;
using ESRI.ArcGIS.Client.Tasks;

namespace ArcGISWPFSDK
{
    public partial class BufferQuery : UserControl
    {
        GeometryService _geometryService;
        QueryTask _queryTask;
        GraphicsLayer _pointAndBufferGraphicsLayer;
        GraphicsLayer _resultsGraphicsLayer;

        public BufferQuery()
        {
            InitializeComponent();

            _geometryService =
            new GeometryService("http://tasks.arcgisonline.com/ArcGIS/rest/services/Geometry/GeometryServer");
            _geometryService.BufferCompleted += GeometryService_BufferCompleted;
            _geometryService.Failed += GeometryService_Failed;

            _queryTask = new QueryTask("http://sampleserver3.arcgisonline.com/ArcGIS/rest/services/BloomfieldHillsMichigan/Parcels/MapServer/2");
            _queryTask.ExecuteCompleted += QueryTask_ExecuteCompleted;
            _queryTask.Failed += QueryTask_Failed;

            _pointAndBufferGraphicsLayer = MyMap.Layers["MyGraphicsLayer"] as GraphicsLayer;
            _resultsGraphicsLayer = MyMap.Layers["MyResultsGraphicsLayer"] as GraphicsLayer;
        }

        private void MyMap_MouseClick(object sender, ESRI.ArcGIS.Client.Map.MouseEventArgs e)
        {
            _geometryService.CancelAsync();
            _queryTask.CancelAsync();

            Graphic clickGraphic = new Graphic();
            clickGraphic.Symbol = LayoutRoot.Resources["DefaultMarkerSymbol"] as ESRI.ArcGIS.Client.Symbols.Symbol;
            clickGraphic.Geometry = e.MapPoint;
            // Input spatial reference for buffer operation defined by first feature of input geometry array
            clickGraphic.Geometry.SpatialReference = MyMap.SpatialReference;

            _pointAndBufferGraphicsLayer.ClearGraphics();
            _resultsGraphicsLayer.ClearGraphics();

            clickGraphic.SetZIndex(2);
            _pointAndBufferGraphicsLayer.Graphics.Add(clickGraphic);

            // If buffer spatial reference is GCS and unit is linear, geometry service will do geodesic buffering
            ESRI.ArcGIS.Client.Tasks.BufferParameters bufferParams = new ESRI.ArcGIS.Client.Tasks.BufferParameters()
            {
                BufferSpatialReference = new SpatialReference(4326),
                OutSpatialReference = MyMap.SpatialReference,
                Unit = LinearUnit.Meter,
            };
            bufferParams.Distances.Add(100);
            bufferParams.Features.Add(clickGraphic);

            _geometryService.BufferAsync(bufferParams);
        }

        void GeometryService_BufferCompleted(object sender, GraphicsEventArgs args)
        {
            Graphic bufferGraphic = new Graphic();
            bufferGraphic.Geometry = args.Results[0].Geometry;
            bufferGraphic.Symbol = LayoutRoot.Resources["BufferSymbol"] as ESRI.ArcGIS.Client.Symbols.Symbol;
            bufferGraphic.SetZIndex(1);

            _pointAndBufferGraphicsLayer.Graphics.Add(bufferGraphic);

            ESRI.ArcGIS.Client.Tasks.Query query = new ESRI.ArcGIS.Client.Tasks.Query();
            query.ReturnGeometry = true;
            query.OutSpatialReference = MyMap.SpatialReference;
            query.Geometry = bufferGraphic.Geometry;
            query.OutFields.Add("OWNERNME1");
            _queryTask.ExecuteAsync(query);
        }

        private void QueryTask_ExecuteCompleted(object sender, QueryEventArgs args)
        {
            if (args.FeatureSet.Features.Count < 1)
            {
                MessageBox.Show("No features found");
                return;
            }

            foreach (Graphic selectedGraphic in args.FeatureSet.Features)
            {
                selectedGraphic.Symbol = LayoutRoot.Resources["ParcelSymbol"] as ESRI.ArcGIS.Client.Symbols.Symbol;
                _resultsGraphicsLayer.Graphics.Add(selectedGraphic);
            }
        }

        private void GeometryService_Failed(object sender, TaskFailedEventArgs args)
        {
            MessageBox.Show("Geometry service failed: " + args.Error);
        }

        private void QueryTask_Failed(object sender, TaskFailedEventArgs args)
        {
            MessageBox.Show("Query failed: " + args.Error);
        }
    }
}

VB.NET

Imports System.Windows
Imports System.Windows.Controls
Imports ESRI.ArcGIS.Client
Imports ESRI.ArcGIS.Client.Geometry
Imports ESRI.ArcGIS.Client.Tasks

Namespace ArcGISWPFSDK
    Partial Public Class BufferQuery
        Inherits UserControl
        Private _geometryService As GeometryService
        Private _queryTask As QueryTask
        Private _pointAndBufferGraphicsLayer As GraphicsLayer
        Private _resultsGraphicsLayer As GraphicsLayer

        Public Sub New()
            InitializeComponent()

            _geometryService = New GeometryService("http://tasks.arcgisonline.com/ArcGIS/rest/services/Geometry/GeometryServer")
            AddHandler _geometryService.BufferCompleted, AddressOf GeometryService_BufferCompleted
            AddHandler _geometryService.Failed, AddressOf GeometryService_Failed

            _queryTask = New QueryTask("http://sampleserver3.arcgisonline.com/ArcGIS/rest/services/BloomfieldHillsMichigan/Parcels/MapServer/2")
            AddHandler _queryTask.ExecuteCompleted, AddressOf QueryTask_ExecuteCompleted
            AddHandler _queryTask.Failed, AddressOf QueryTask_Failed

            _pointAndBufferGraphicsLayer = TryCast(MyMap.Layers("MyGraphicsLayer"), GraphicsLayer)
            _resultsGraphicsLayer = TryCast(MyMap.Layers("MyResultsGraphicsLayer"), GraphicsLayer)
        End Sub

        Private Sub MyMap_MouseClick(sender As Object, e As ESRI.ArcGIS.Client.Map.MouseEventArgs)
            _geometryService.CancelAsync()
            _queryTask.CancelAsync()

            Dim clickGraphic As New Graphic()
            clickGraphic.Symbol = TryCast(LayoutRoot.Resources("DefaultMarkerSymbol"), ESRI.ArcGIS.Client.Symbols.Symbol)
            clickGraphic.Geometry = e.MapPoint
            ' Input spatial reference for buffer operation defined by first feature of input geometry array
            clickGraphic.Geometry.SpatialReference = MyMap.SpatialReference

            _pointAndBufferGraphicsLayer.ClearGraphics()
            _resultsGraphicsLayer.ClearGraphics()

            clickGraphic.SetZIndex(2)
            _pointAndBufferGraphicsLayer.Graphics.Add(clickGraphic)

            ' If buffer spatial reference is GCS and unit is linear, geometry service will do geodesic buffering
            Dim bufferParams As New ESRI.ArcGIS.Client.Tasks.BufferParameters() With { _
             .BufferSpatialReference = New SpatialReference(4326), _
             .OutSpatialReference = MyMap.SpatialReference, _
             .Unit = LinearUnit.Meter _
            }
            bufferParams.Distances.Add(100)
            bufferParams.Features.Add(clickGraphic)

            _geometryService.BufferAsync(bufferParams)
        End Sub

        Private Sub GeometryService_BufferCompleted(sender As Object, args As GraphicsEventArgs)
            Dim bufferGraphic As New Graphic()
            bufferGraphic.Geometry = args.Results(0).Geometry
            bufferGraphic.Symbol = TryCast(LayoutRoot.Resources("BufferSymbol"), ESRI.ArcGIS.Client.Symbols.Symbol)
            bufferGraphic.SetZIndex(1)

            _pointAndBufferGraphicsLayer.Graphics.Add(bufferGraphic)

            Dim query As New ESRI.ArcGIS.Client.Tasks.Query()
            query.ReturnGeometry = True
            query.OutSpatialReference = MyMap.SpatialReference
            query.Geometry = bufferGraphic.Geometry
            query.OutFields.Add("OWNERNME1")
            _queryTask.ExecuteAsync(query)
        End Sub

        Private Sub QueryTask_ExecuteCompleted(sender As Object, args As QueryEventArgs)
            If args.FeatureSet.Features.Count < 1 Then
                MessageBox.Show("No features found")
                Return
            End If

            For Each selectedGraphic As Graphic In args.FeatureSet.Features
                selectedGraphic.Symbol = TryCast(LayoutRoot.Resources("ParcelSymbol"), ESRI.ArcGIS.Client.Symbols.Symbol)
                _resultsGraphicsLayer.Graphics.Add(selectedGraphic)
            Next
        End Sub

        Private Sub GeometryService_Failed(sender As Object, args As TaskFailedEventArgs)
            MessageBox.Show("Geometry service failed: " & Convert.ToString(args.[Error]))
        End Sub

        Private Sub QueryTask_Failed(sender As Object, args As TaskFailedEventArgs)
            MessageBox.Show("Query failed: " & Convert.ToString(args.[Error]))
        End Sub
    End Class
End Namespace