Query with a Buffer

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

In the code-behind, a LocalGeometryService 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.LocalBufferQuery"
    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>
            <BooleanToVisibilityConverter x:Key="BooleanToVisibilityConverter"/>
            <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" WrapAround="True" Extent="-15000000,2000000,-7000000,8000000" Background="#FFE3E3E3" MinimumResolution="2445.98490512499">
            <esri:ArcGISLocalTiledLayer ID="BaseMap" Path="..\\Data\\TPKs\\Topographic.tpk"/>
            <esri:GraphicsLayer ID="MyResultsGraphicsLayer">
                <esri:GraphicsLayer.MapTip>
                    <Border BorderBrush="DarkGray" Background="Azure" CornerRadius="3" BorderThickness="1" Padding="3">
                        <StackPanel Orientation="Vertical">
                            <TextBlock Text="State:" FontWeight="Bold" HorizontalAlignment="Left" VerticalAlignment="Center" Foreground="Black"  />
                            <TextBlock Text="{Binding [STATE_NAME]}" 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 States within 5 degrees of the location." 
                 Width="200" Margin="30,20,30,25" HorizontalAlignment="Left" TextWrapping="Wrap" Foreground="Black" />
        </Grid>
        <ProgressBar x:Name="MyProgressBar" IsIndeterminate="True" VerticalAlignment="Bottom" Width="200" Height="20" Margin="10" Visibility="{Binding Path=IsBusy, Converter={StaticResource BooleanToVisibilityConverter}}"></ProgressBar>
    </Grid>
</UserControl>

C#

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

namespace ArcGISWPFSDK
{
    public partial class LocalBufferQuery : UserControl, INotifyPropertyChanged
    {
        public event PropertyChangedEventHandler PropertyChanged;

        private bool _isBusy = true;

        public bool IsBusy
        {
            get
            {
                return _isBusy;
            }
            set
            {
                _isBusy = value;

                if (PropertyChanged != null)
                {

                    PropertyChanged(this, new PropertyChangedEventArgs("IsBusy"));
                }
            }
        }    
    
        QueryTask _queryTask;
        Query _query;
        GraphicsLayer _pointAndBufferGraphicsLayer;
        GraphicsLayer _resultsGraphicsLayer;
        GeometryService _geometryService;
        LocalMapService _mapService;


        public LocalBufferQuery()
        {
            InitializeComponent();


            LocalGeometryService localGeometryService = new LocalGeometryService();
            localGeometryService.StartCompleted += (sender, eventargs) =>
            {
                LocalGeometryService lgs = sender as LocalGeometryService;
                _geometryService = new GeometryService();
                _geometryService.Url = lgs.UrlGeometryService;
                _geometryService.BufferCompleted += GeometryService_BufferCompleted;
                _geometryService.Failed += GeometryService_Failed;
                MyMap.MouseClick += MyMap_MouseClick;

            };
            localGeometryService.StartAsync();

            LocalMapService.GetServiceAsync("..\\Data\\MPKS\\USCitiesStates.mpk", (localMapService) =>
            {
                _mapService = localMapService;
                _queryTask = new QueryTask();
                _queryTask.Url = _mapService.UrlMapService + "/2";
                _queryTask.ExecuteCompleted += QueryTask_ExecuteCompleted;
                _queryTask.Failed += QueryTask_Failed;
                DataContext = this;
                IsBusy = false;
            });

            _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();

            Graphic clickGraphic = new Graphic();
            clickGraphic.Symbol = LayoutRoot.Resources["DefaultMarkerSymbol"] as ESRI.ArcGIS.Client.Symbols.Symbol;
            clickGraphic.Geometry = e.MapPoint;
            clickGraphic.Geometry.SpatialReference = MyMap.SpatialReference;
            _pointAndBufferGraphicsLayer.ClearGraphics();
            _resultsGraphicsLayer.ClearGraphics();
            clickGraphic.SetZIndex(2);
            _pointAndBufferGraphicsLayer.Graphics.Add(clickGraphic);
            ESRI.ArcGIS.Client.Tasks.BufferParameters bufferParams = new ESRI.ArcGIS.Client.Tasks.BufferParameters()
            {
                BufferSpatialReference = new SpatialReference(4326),
                OutSpatialReference = MyMap.SpatialReference,
                Unit = LinearUnit.Degree,
            };
            bufferParams.Distances.Add(5);
            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);
            _query = new ESRI.ArcGIS.Client.Tasks.Query();
            _query.ReturnGeometry = true;
            _query.OutSpatialReference = MyMap.SpatialReference;
            _query.Geometry = bufferGraphic.Geometry;
            _query.OutFields.Add("*");
            _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
Imports ESRI.ArcGIS.Client.Local
Imports System.ComponentModel

Namespace ArcGISWPFSDK
    Partial Public Class LocalBufferQuery
        Inherits UserControl
        Implements INotifyPropertyChanged
        Public Event PropertyChanged As PropertyChangedEventHandler Implements INotifyPropertyChanged.PropertyChanged
        Private _isBusy As Boolean = True
        Public Property IsBusy() As Boolean
            Get
                Return _isBusy
            End Get
            Set(value As Boolean)
                _isBusy = value

                RaiseEvent PropertyChanged(Me, New PropertyChangedEventArgs("IsBusy"))
            End Set
        End Property
        Private _queryTask As QueryTask
        Private _query As Query
        Private _pointAndBufferGraphicsLayer As GraphicsLayer
        Private _resultsGraphicsLayer As GraphicsLayer
        Private _geometryService As GeometryService
        Private _mapService As LocalMapService


        Public Sub New()
            InitializeComponent()


            Dim localGeometryService As New LocalGeometryService()
            AddHandler localGeometryService.StartCompleted, AddressOf localGeometryService_StartCompleted
            localGeometryService.StartAsync()

            LocalMapService.GetServiceAsync("..\Data\MPKS\USCitiesStates.mpk", Function(localMapService__1)
                                                                                   _mapService = localMapService__1
                                                                                   _queryTask = New QueryTask()
                                                                                   _queryTask.Url = _mapService.UrlMapService & "/2"
                                                                                   AddHandler _queryTask.ExecuteCompleted, AddressOf QueryTask_ExecuteCompleted
                                                                                   AddHandler _queryTask.Failed, AddressOf QueryTask_Failed
                                                                                   DataContext = Me
                                                                                   IsBusy = False
                                                                               End Function)

            _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()

            Dim clickGraphic As New Graphic()
            clickGraphic.Symbol = TryCast(LayoutRoot.Resources("DefaultMarkerSymbol"), ESRI.ArcGIS.Client.Symbols.Symbol)
            clickGraphic.Geometry = e.MapPoint
            clickGraphic.Geometry.SpatialReference = MyMap.SpatialReference
            _pointAndBufferGraphicsLayer.ClearGraphics()
            _resultsGraphicsLayer.ClearGraphics()
            clickGraphic.SetZIndex(2)
            _pointAndBufferGraphicsLayer.Graphics.Add(clickGraphic)
            Dim bufferParams As New ESRI.ArcGIS.Client.Tasks.BufferParameters() With { _
             .BufferSpatialReference = New SpatialReference(4326), _
             .OutSpatialReference = MyMap.SpatialReference, _
             .Unit = LinearUnit.Degree _
            }
            bufferParams.Distances.Add(5)
            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)
            _query = New ESRI.ArcGIS.Client.Tasks.Query()
            _query.ReturnGeometry = True
            _query.OutSpatialReference = MyMap.SpatialReference
            _query.Geometry = bufferGraphic.Geometry
            _query.OutFields.Add("*")
            _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

        Private Sub localGeometryService_StartCompleted(sender As Object, eventargs As ComponentModel.AsyncCompletedEventArgs)
            Dim lgs As LocalGeometryService = TryCast(sender, LocalGeometryService)
            _geometryService = New GeometryService()
            _geometryService.Url = lgs.UrlGeometryService
            AddHandler _geometryService.BufferCompleted, AddressOf GeometryService_BufferCompleted
            AddHandler _geometryService.Failed, AddressOf GeometryService_Failed

            AddHandler MyMap.MouseClick, AddressOf MyMap_MouseClick
        End Sub

    End Class
End Namespace