Spatial Query

This sample demonstrates using the ArcGIS Runtime SDK for WPF to perform a spatial query on local data and adding the results to the map and a DataGrid. To use the sample, select a drawing tool from the toolbar, then draw a query geometry on the map.

In the sample's code-behind, a QueryTask is used to query a states map service layer based on the geometry drawn. The results are then added as a Graphics to the map and displayed in a DataGrid. The sample also demonstrates specifying a mouse over symbol in XAML for the results graphics and highlighting a graphic when the corresponding row in the DataGrid is moused over.

XAML

<UserControl x:Class="ArcGISWPFSDK.LocalSpatialQuery"
    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:SimpleRenderer x:Key="MySimplePolygonRenderer">
                <esri:SimpleRenderer.Symbol>
                    <esri:SimpleFillSymbol Fill="#440000FF"/>
                </esri:SimpleRenderer.Symbol>
            </esri:SimpleRenderer>
            <Style x:Key="MyCustomRow" TargetType="{x:Type DataGridRow}">
                <Setter Property="IsTabStop" Value="False" />
                <Setter Property="Template">
                    <Setter.Value>
                        <ControlTemplate TargetType="{x:Type DataGridRow}">
                            <Border x:Name="DGR_Border"
                                Background="{TemplateBinding Background}"
                                BorderBrush="{TemplateBinding BorderBrush}"
                                BorderThickness="{TemplateBinding BorderThickness}"
                                SnapsToDevicePixels="True">
                                <SelectiveScrollingGrid>
                                    <Grid.ColumnDefinitions>
                                        <ColumnDefinition Width="Auto"/>
                                        <ColumnDefinition Width="*"/>
                                    </Grid.ColumnDefinitions>
                                    <Grid.RowDefinitions>
                                        <RowDefinition Height="*"/>
                                        <RowDefinition Height="Auto"/>
                                    </Grid.RowDefinitions>
                                    <DataGridCellsPresenter Grid.Column="1"
                                         ItemsPanel="{TemplateBinding ItemsPanel}"
                                         SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
                                    <DataGridDetailsPresenter 
                                        SelectiveScrollingGrid.SelectiveScrollingOrientation="{Binding RelativeSource={RelativeSource AncestorType={x:Type DataGrid}}, 
                                        Path=AreRowDetailsFrozen, Converter={x:Static DataGrid.RowDetailsScrollingConverter}, ConverterParameter={x:Static SelectiveScrollingOrientation.Vertical}}"
                                            Grid.Column="1" Grid.Row="1" Visibility="{TemplateBinding DetailsVisibility}" />
                                    <DataGridRowHeader SelectiveScrollingGrid.SelectiveScrollingOrientation="Vertical"  Grid.RowSpan="2"
                                    Visibility="{Binding RelativeSource={RelativeSource AncestorType={x:Type DataGrid}}, Path=HeadersVisibility, Converter={x:Static DataGrid.HeadersVisibilityConverter}, ConverterParameter={x:Static DataGridHeadersVisibility.Row}}"/>
                                </SelectiveScrollingGrid>
                            </Border>
                            <ControlTemplate.Triggers>
                                <Trigger Property="DataGridRow.IsMouseOver" Value="True">
                                    <Setter Property="Background" Value="#8800FFFF" />
                                    <Setter Property="Foreground" Value="Black" />
                                </Trigger>
                            </ControlTemplate.Triggers>
                        </ControlTemplate>
                    </Setter.Value>
                </Setter>
            </Style>
            <esri:SimpleMarkerSymbol x:Key="DefaultMarkerSymbol" Color="Red" Size="12" Style="Circle" />
            <esri:SimpleLineSymbol x:Key="DefaultLineSymbol" Color="Red" Width="4" />
            <esri:FillSymbol x:Key="DefaultFillSymbol" >
                <esri:FillSymbol.ControlTemplate>
                    <ControlTemplate>
                        <Path x:Name="Element" IsHitTestVisible="False" Fill="#66FF0000" 
                            Stroke="Red" StrokeThickness="1"/>
                    </ControlTemplate>
                </esri:FillSymbol.ControlTemplate>
            </esri:FillSymbol>
            <esri:FillSymbol x:Key="ResultsFillSymbol">
                <esri:FillSymbol.ControlTemplate>
                    <ControlTemplate x:Name="CustomPolygonTemplate">
                        <Grid>
                            <VisualStateManager.VisualStateGroups>
                                <VisualStateGroup x:Name="CommonStates">
                                    <VisualState x:Name="Normal">
                                        <Storyboard>
                                            <ColorAnimation Storyboard.TargetName="Element"
                                                Storyboard.TargetProperty="(Fill).(Color)"
                                                To="#880000FF" Duration="0:0:0.1" />
                                        </Storyboard>
                                    </VisualState>
                                    <VisualState x:Name="MouseOver">
                                        <Storyboard>
                                            <ColorAnimation Storyboard.TargetName="Element"
                                                Storyboard.TargetProperty="(Fill).(Color)"
                                                To="#8800FFFF" Duration="0:0:0.1" />
                                        </Storyboard>
                                    </VisualState>
                                    <VisualState x:Name="Selected">
                                        <Storyboard>
                                            <ColorAnimation Storyboard.TargetName="Element"
                                                Storyboard.TargetProperty="(Fill).(Color)"
                                                To="#8800FFFF" Duration="0:0:0.1" />
                                        </Storyboard>
                                    </VisualState>
                                </VisualStateGroup>
                            </VisualStateManager.VisualStateGroups>
                            <Path x:Name="Element" Stroke="Blue" Fill="#880000FF"
                                StrokeStartLineCap="Round" StrokeThickness="2" 
                                StrokeLineJoin="Round" StrokeEndLineCap="Round" />
                        </Grid>
                    </ControlTemplate>
                </esri:FillSymbol.ControlTemplate>
            </esri:FillSymbol>
            <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:ArcGISLocalFeatureLayer ID="States" LayerName="States"
                   Path="..\\Data\\MPKS\\USCitiesStates.mpk"        
                    Renderer="{StaticResource MySimplePolygonRenderer}"            
                    OutFields="*"/>
            <esri:GraphicsLayer ID="MySelectionGraphicsLayer" 
                                    MouseEnter="GraphicsLayer_MouseEnter" 
                                    MouseLeave="GraphicsLayer_MouseLeave"/>
        </esri:Map>


        <Border Background="{StaticResource PanelGradient}" BorderThickness="1" CornerRadius="5"
                HorizontalAlignment="Right" VerticalAlignment="Top"
                Margin="10" BorderBrush="{StaticResource PanelGradient}">
            <Border.Effect>
                <DropShadowEffect/>
            </Border.Effect>
            <Grid Margin="10" Background="White">
                <StackPanel Orientation="Vertical">
                    <StackPanel x:Name="MyStackPanel" Orientation="Horizontal" Width="483" Height="60">
                        <Button Tag="DrawPoint" Margin="5" Click="Tool_Click"  
                                ToolTipService.ToolTip="Select with a point">
                            <Image Source="/Assets/images/DrawPoint.png" Margin="2" />
                        </Button>
                        <Button Tag="DrawPolyline" Margin="5" Click="Tool_Click"
                                ToolTipService.ToolTip="Select with a polyline">
                            <Image Source="/Assets/images/DrawPolyline.png" Margin="2" />
                        </Button>
                        <Button Tag="DrawPolygon" Margin="5" Click="Tool_Click"
                                ToolTipService.ToolTip="Select with a polygon">
                            <Image Source="/Assets/images/DrawPolygon.png" Margin="5" />
                        </Button>
                        <Button Tag="DrawRectangle" Margin="5" Click="Tool_Click"
                                ToolTipService.ToolTip="Select with a rectangle">
                            <Image Source="/Assets/images/DrawRectangle.png" Margin="2" />
                        </Button>
                        <Button Tag="DrawFreehand" Margin="5" Click="Tool_Click"
                                ToolTipService.ToolTip="Select with a freehand line">
                            <Image Source="/Assets/images/DrawFreehand.png" Margin="5" />
                        </Button>
                        <Button Tag="DrawCircle" Margin="5" Click="Tool_Click"
                                ToolTipService.ToolTip="Select with a circle">
                            <Image Source="/Assets/images/DrawCircle.png" Margin="2" />
                        </Button>
                        <Button Tag="DrawEllipse" Margin="5" Click="Tool_Click"
                                ToolTipService.ToolTip="Select with an ellipse">
                            <Image Source="/Assets/images/DrawEllipse.png" Margin="2" />
                        </Button>
                        <Button Tag="ClearStopDraw" Margin="5" Click="Tool_Click"
                                Style="{x:Null}"
                                ToolTipService.ToolTip="Clear map">
                            <Image Source="/Assets/images/StopDraw.png" Margin="2" />
                        </Button>
                    </StackPanel>
                </StackPanel>
            </Grid>
        </Border>

        <Border x:Name="ResultsDisplay" Background="{StaticResource PanelGradient}" BorderThickness="1" CornerRadius="5"
                HorizontalAlignment="Right"  VerticalAlignment="Bottom" Visibility="Collapsed"
                Margin="5" Padding="10" BorderBrush="Black">
            <Grid>
                <TextBlock x:Name="DataDisplayTitle" Text="Search Results" Foreground="White" FontSize="12" Canvas.Left="10" Canvas.Top="4" />
                <DataGrid x:Name="QueryDetailsDataGrid" Width="Auto" Height="170" AutoGenerateColumns="False" HeadersVisibility="Column" Background="White" 
                             IsReadOnly="True" Canvas.Left="10" Canvas.Top="25" HorizontalScrollBarVisibility="Hidden"
                             RowStyle="{StaticResource MyCustomRow}" CanUserSortColumns="True"
                             SelectionChanged="QueryDetailsDataGrid_SelectionChanged"
                             LoadingRow="QueryDetailsDataGrid_LoadingRow">
                    <DataGrid.Columns>
                        <DataGridTextColumn Binding="{Binding Attributes[STATE_NAME]}" IsReadOnly="True" Width="100" CanUserSort="True" Header="State Name"/>
                        <DataGridTextColumn Binding="{Binding Attributes[SUB_REGION]}" IsReadOnly="True" Width="110" CanUserSort="False" Header="Region"/>
                        <DataGridTextColumn Binding="{Binding Attributes[STATE_FIPS]}" IsReadOnly="True" Width="45" CanUserSort="False" Header="FIPS"/>
                        <DataGridTextColumn Binding="{Binding Attributes[STATE_ABBR]}" IsReadOnly="True" Width="85" CanUserSort="False" Header="Abbreviation"/>
                        <DataGridTextColumn Binding="{Binding Attributes[POP2000]}" IsReadOnly="True" Width="103"  CanUserSort="False" Header="Population 2000"/>
                        <DataGridTextColumn Binding="{Binding Attributes[POP2010]}" IsReadOnly="True" Width="100" CanUserSort="False" Header="Population 2010"/>
                    </DataGrid.Columns>
                </DataGrid>
            </Grid>
        </Border>
        <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 System.Windows.Data;
using System.Windows.Input;
using ESRI.ArcGIS.Client;
using ESRI.ArcGIS.Client.Local;
using ESRI.ArcGIS.Client.Symbols;
using ESRI.ArcGIS.Client.Tasks;
using ESRI.ArcGIS.Client.ValueConverters;
using System.ComponentModel;
using System;

namespace ArcGISWPFSDK
{
    public partial class LocalSpatialQuery : 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"));
                }
            }
        }    
    
        private Draw MyDrawObject;
        LocalMapService _mapService;
        GraphicsLayer selectionGraphicslayer;

        public LocalSpatialQuery()
        {
            InitializeComponent();

            selectionGraphicslayer = MyMap.Layers["MySelectionGraphicsLayer"] as GraphicsLayer;
            LocalMapService.GetServiceAsync("..\\Data\\MPKS\\USCitiesStates.mpk", (localMapService) =>
            {
                _mapService = localMapService;
                DataContext = this;
                IsBusy = false;
            });

            MyDrawObject = new Draw(MyMap)
            {
                LineSymbol = LayoutRoot.Resources["DefaultLineSymbol"] as SimpleLineSymbol,
                FillSymbol = LayoutRoot.Resources["DefaultFillSymbol"] as FillSymbol
            };
            MyDrawObject.DrawComplete += MyDrawSurface_DrawComplete;
        }

        private void UnSelectTools()
        {
            foreach (UIElement element in MyStackPanel.Children)
                if (element is Button)
                    VisualStateManager.GoToState((element as Button), "UnSelected", false);
        }

        private void Tool_Click(object sender, RoutedEventArgs e)
        {
            UnSelectTools();

            VisualStateManager.GoToState(sender as Button, "Selected", false);

            switch ((sender as Button).Tag as string)
            {
                case "DrawPoint":
                    MyDrawObject.DrawMode = DrawMode.Point;
                    break;
                case "DrawPolyline":
                    MyDrawObject.DrawMode = DrawMode.Polyline;
                    break;
                case "DrawPolygon":
                    MyDrawObject.DrawMode = DrawMode.Polygon;
                    break;
                case "DrawRectangle":
                    MyDrawObject.DrawMode = DrawMode.Rectangle;
                    break;
                case "DrawFreehand":
                    MyDrawObject.DrawMode = DrawMode.Freehand;
                    break;
                case "DrawCircle":
                    MyDrawObject.DrawMode = DrawMode.Circle;
                    break;
                case "DrawEllipse":
                    MyDrawObject.DrawMode = DrawMode.Ellipse;
                    break;
                default:
                    MyDrawObject.DrawMode = DrawMode.None;
                    selectionGraphicslayer.ClearGraphics();
                    QueryDetailsDataGrid.ItemsSource = null;
                    ResultsDisplay.Visibility = Visibility.Collapsed;
                    break;
            }
            MyDrawObject.IsEnabled = (MyDrawObject.DrawMode != DrawMode.None);
        }

        private void MyDrawSurface_DrawComplete(object sender, ESRI.ArcGIS.Client.DrawEventArgs args)
        {
            GraphicsLayer selectionGraphicslayer = MyMap.Layers["MySelectionGraphicsLayer"] as GraphicsLayer;
            selectionGraphicslayer.ClearGraphics();

            QueryTask queryTask = new QueryTask();
            queryTask.Url = _mapService.UrlMapService + "/2";
            queryTask.ExecuteCompleted += QueryTask_ExecuteCompleted;
            queryTask.Failed += QueryTask_Failed;
            Binding resultFeaturesBinding = new Binding("LastResult.Features");
            resultFeaturesBinding.Source = queryTask;
            QueryDetailsDataGrid.SetBinding(DataGrid.ItemsSourceProperty, resultFeaturesBinding);
            Query query = new ESRI.ArcGIS.Client.Tasks.Query();
            query.OutFields.AddRange(new string[] { "STATE_NAME", "SUB_REGION", "STATE_FIPS", "STATE_ABBR", "POP2000", "POP2010" });
            query.Geometry = args.Geometry;
            query.ReturnGeometry = true;
            queryTask.ExecuteAsync(query);
        }


        private void QueryTask_ExecuteCompleted(object sender, ESRI.ArcGIS.Client.Tasks.QueryEventArgs args)
        {
            FeatureSet featureSet = args.FeatureSet;

            if (featureSet == null || featureSet.Features.Count < 1)
            {
                MessageBox.Show("No features returned from query");
                return;
            }

            GraphicsLayer graphicsLayer = MyMap.Layers["MySelectionGraphicsLayer"] as GraphicsLayer;
            if (featureSet != null && featureSet.Features.Count > 0)
            {
                foreach (Graphic feature in featureSet.Features)
                {
                    feature.Symbol = LayoutRoot.Resources["ResultsFillSymbol"] as FillSymbol;
                    graphicsLayer.Graphics.Insert(0, feature);
                }
                ResultsDisplay.Visibility = Visibility.Visible;
            }
            MyDrawObject.IsEnabled = false;
        }

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

        private void GraphicsLayer_MouseEnter(object sender, GraphicMouseEventArgs args)
        {
            QueryDetailsDataGrid.Focus();
            QueryDetailsDataGrid.SelectedItem = args.Graphic;
            QueryDetailsDataGrid.CurrentColumn = QueryDetailsDataGrid.Columns[0];
            QueryDetailsDataGrid.ScrollIntoView(QueryDetailsDataGrid.SelectedItem, QueryDetailsDataGrid.Columns[0]);
        }

        private void GraphicsLayer_MouseLeave(object sender, GraphicMouseEventArgs args)
        {
            QueryDetailsDataGrid.Focus();
            QueryDetailsDataGrid.SelectedItem = null;
        }

        private void QueryDetailsDataGrid_SelectionChanged(object sender, SelectionChangedEventArgs e)
        {
            foreach (Graphic g in e.AddedItems)
                g.Select();

            foreach (Graphic g in e.RemovedItems)
                g.UnSelect();
        }

        private void QueryDetailsDataGrid_LoadingRow(object sender, DataGridRowEventArgs e)
        {
            e.Row.MouseEnter += Row_MouseEnter;
            e.Row.MouseLeave += Row_MouseLeave;
        }

        void Row_MouseEnter(object sender, MouseEventArgs e)
        {
            (((System.Windows.FrameworkElement)(sender)).DataContext as Graphic).Select();
        }

        void Row_MouseLeave(object sender, MouseEventArgs e)
        {
            DataGridRow row = sender as DataGridRow;
            Graphic g = ((System.Windows.FrameworkElement)(sender)).DataContext as Graphic;

            if (!QueryDetailsDataGrid.SelectedItems.Contains(g))
                g.UnSelect();
        }
    }
}

VB.NET

Imports System.Windows
Imports System.Windows.Controls
Imports System.Windows.Data
Imports System.Windows.Input
Imports ESRI.ArcGIS.Client
Imports ESRI.ArcGIS.Client.Local
Imports ESRI.ArcGIS.Client.Symbols
Imports ESRI.ArcGIS.Client.Tasks
Imports ESRI.ArcGIS.Client.ValueConverters
Imports System.ComponentModel

Namespace ArcGISWPFSDK
    Partial Public Class LocalSpatialQuery
        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 MyDrawObject As Draw
        Private _mapService As LocalMapService
        Private selectionGraphicslayer As GraphicsLayer

        Public Sub New()
            InitializeComponent()

            selectionGraphicslayer = TryCast(MyMap.Layers("MySelectionGraphicsLayer"), GraphicsLayer)
            LocalMapService.GetServiceAsync("..\Data\MPKS\USCitiesStates.mpk", Function(localMapService__1)
                                                                                   _mapService = localMapService__1
                                                                                   DataContext = Me
                                                                                   IsBusy = False
                                                                               End Function)

            MyDrawObject = New Draw(MyMap) With { _
             .LineSymbol = TryCast(LayoutRoot.Resources("DefaultLineSymbol"), SimpleLineSymbol), _
             .FillSymbol = TryCast(LayoutRoot.Resources("DefaultFillSymbol"), FillSymbol) _
            }
            AddHandler MyDrawObject.DrawComplete, AddressOf MyDrawSurface_DrawComplete
        End Sub

        Private Sub UnSelectTools()
            For Each element As UIElement In MyStackPanel.Children
                If TypeOf element Is Button Then
                    VisualStateManager.GoToState(TryCast(element, Button), "UnSelected", False)
                End If
            Next
        End Sub

        Private Sub Tool_Click(sender As Object, e As RoutedEventArgs)
            UnSelectTools()

            VisualStateManager.GoToState(TryCast(sender, Button), "Selected", False)

            Select Case TryCast(TryCast(sender, Button).Tag, String)
                Case "DrawPoint"
                    MyDrawObject.DrawMode = DrawMode.Point
                    Exit Select
                Case "DrawPolyline"
                    MyDrawObject.DrawMode = DrawMode.Polyline
                    Exit Select
                Case "DrawPolygon"
                    MyDrawObject.DrawMode = DrawMode.Polygon
                    Exit Select
                Case "DrawRectangle"
                    MyDrawObject.DrawMode = DrawMode.Rectangle
                    Exit Select
                Case "DrawFreehand"
                    MyDrawObject.DrawMode = DrawMode.Freehand
                    Exit Select
                Case "DrawCircle"
                    MyDrawObject.DrawMode = DrawMode.Circle
                    Exit Select
                Case "DrawEllipse"
                    MyDrawObject.DrawMode = DrawMode.Ellipse
                    Exit Select
                Case Else
                    MyDrawObject.DrawMode = DrawMode.None
                    selectionGraphicslayer.ClearGraphics()
                    QueryDetailsDataGrid.ItemsSource = Nothing
                    ResultsDisplay.Visibility = Visibility.Collapsed
                    Exit Select
            End Select
            MyDrawObject.IsEnabled = (MyDrawObject.DrawMode <> DrawMode.None)
        End Sub

        Private Sub MyDrawSurface_DrawComplete(sender As Object, args As ESRI.ArcGIS.Client.DrawEventArgs)
            Dim selectionGraphicslayer As GraphicsLayer = TryCast(MyMap.Layers("MySelectionGraphicsLayer"), GraphicsLayer)
            selectionGraphicslayer.ClearGraphics()

            Dim queryTask As New QueryTask()
            queryTask.Url = _mapService.UrlMapService & "/2"
            AddHandler queryTask.ExecuteCompleted, AddressOf QueryTask_ExecuteCompleted
            AddHandler queryTask.Failed, AddressOf QueryTask_Failed
            Dim resultFeaturesBinding As New Binding("LastResult.Features")
            resultFeaturesBinding.Source = queryTask
            QueryDetailsDataGrid.SetBinding(DataGrid.ItemsSourceProperty, resultFeaturesBinding)
            Dim query As Query = New ESRI.ArcGIS.Client.Tasks.Query()
            query.OutFields.AddRange(New String() {"STATE_NAME", "SUB_REGION", "STATE_FIPS", "STATE_ABBR", "POP2000", "POP2010"})
            query.Geometry = args.Geometry
            query.ReturnGeometry = True
            queryTask.ExecuteAsync(query)
        End Sub


        Private Sub QueryTask_ExecuteCompleted(sender As Object, args As ESRI.ArcGIS.Client.Tasks.QueryEventArgs)
            Dim featureSet As FeatureSet = args.FeatureSet

            If featureSet Is Nothing OrElse featureSet.Features.Count < 1 Then
                MessageBox.Show("No features returned from query")
                Return
            End If

            Dim graphicsLayer As GraphicsLayer = TryCast(MyMap.Layers("MySelectionGraphicsLayer"), GraphicsLayer)
            If featureSet IsNot Nothing AndAlso featureSet.Features.Count > 0 Then
                For Each feature As Graphic In featureSet.Features
                    feature.Symbol = TryCast(LayoutRoot.Resources("ResultsFillSymbol"), FillSymbol)
                    graphicsLayer.Graphics.Insert(0, feature)
                Next
                ResultsDisplay.Visibility = Visibility.Visible
            End If
            MyDrawObject.IsEnabled = False
        End Sub

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

        Private Sub GraphicsLayer_MouseEnter(sender As Object, args As GraphicMouseEventArgs)
            QueryDetailsDataGrid.Focus()
            QueryDetailsDataGrid.SelectedItem = args.Graphic
            QueryDetailsDataGrid.CurrentColumn = QueryDetailsDataGrid.Columns(0)
            QueryDetailsDataGrid.ScrollIntoView(QueryDetailsDataGrid.SelectedItem, QueryDetailsDataGrid.Columns(0))
        End Sub

        Private Sub GraphicsLayer_MouseLeave(sender As Object, args As GraphicMouseEventArgs)
            QueryDetailsDataGrid.Focus()
            QueryDetailsDataGrid.SelectedItem = Nothing
        End Sub

        Private Sub QueryDetailsDataGrid_SelectionChanged(sender As Object, e As SelectionChangedEventArgs)
            For Each g As Graphic In e.AddedItems
                g.[Select]()
            Next

            For Each g As Graphic In e.RemovedItems
                g.UnSelect()
            Next
        End Sub

        Private Sub QueryDetailsDataGrid_LoadingRow(sender As Object, e As DataGridRowEventArgs)
            AddHandler e.Row.MouseEnter, AddressOf Row_MouseEnter
            AddHandler e.Row.MouseLeave, AddressOf Row_MouseLeave
        End Sub

        Private Sub Row_MouseEnter(sender As Object, e As MouseEventArgs)
            TryCast(DirectCast(sender, System.Windows.FrameworkElement).DataContext, Graphic).[Select]()
        End Sub

        Private Sub Row_MouseLeave(sender As Object, e As MouseEventArgs)
            Dim row As DataGridRow = TryCast(sender, DataGridRow)
            Dim g As Graphic = TryCast(DirectCast(sender, System.Windows.FrameworkElement).DataContext, Graphic)

            If Not QueryDetailsDataGrid.SelectedItems.Contains(g) Then
                g.UnSelect()
            End If
        End Sub
    End Class
End Namespace