Identify Online

This sample demonstrates performing identify operations. To use the sample, simply click anywhere in the United States to identify features. The results will be shown in the drop-down menu and DataGrid in the upper right corner of the application. View the data for different results by selecting them from the drop-down menu.

In the code-behind, an IdentifyTask is to perform the identify operation. The tasks IdentifyParameters specify to query the geometry of the map click andIto query all the layers in the target map service, which enables the returning of results from multiple layers.

XAML

<UserControl x:Class="ArcGISWPFSDK.Identify"
    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="DefaultPictureSymbol" OffsetX="35" OffsetY="35" 
                 Source="/Assets/Images/i_about.png" />
            <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" Background="White" Extent="-15000000,2000000,-7000000,8000000" MouseClick="QueryPoint_MouseClick" >
            <esri:ArcGISTiledMapServiceLayer ID="StreetMapLayer" 
                      Url="http://services.arcgisonline.com/ArcGIS/rest/services/World_Street_Map/MapServer"/>
            <esri:GraphicsLayer ID="MyGraphicsLayer" />
        </esri:Map>

        <Grid x:Name="IdentifyGrid" HorizontalAlignment="Right" VerticalAlignment="Top" Margin="0,7,7,0" >
            <Rectangle Fill="{StaticResource PanelGradient}" Stroke="Gray" Margin="-5,1,-2,-6" RadiusX="10" RadiusY="10">
                <Rectangle.Effect>
                    <DropShadowEffect/>
                </Rectangle.Effect>
            </Rectangle>
            <TextBlock x:Name="DataDisplayTitleTop" Text="Click on map to identify a feature" Foreground="White" FontSize="12" 
                      Margin="2,8,8,-3" />
            <StackPanel x:Name="IdentifyResultsPanel" Orientation="Vertical" Margin="15" HorizontalAlignment="Center" 
                            VerticalAlignment="Top" Visibility="Collapsed" >
                <ComboBox x:Name="IdentifyComboBox" MinWidth="150" SelectionChanged="cb_SelectionChanged"
                         Margin="2,10,2,2" >
                </ComboBox>
                <ScrollViewer HorizontalScrollBarVisibility="Hidden" VerticalScrollBarVisibility="Auto"  
                         Width="230" MaxHeight="340">
                    <DataGrid x:Name="IdentifyDetailsDataGrid" AutoGenerateColumns="False" HeadersVisibility="None" 
                              Background="White">
                        <DataGrid.Columns>
                            <DataGridTextColumn Width="95" Binding="{Binding Path=Key}" FontWeight="Bold" IsReadOnly="True"/>
                            <DataGridTextColumn Width="115" Binding="{Binding Path=Value}" IsReadOnly="True"/>
                        </DataGrid.Columns>
                    </DataGrid>
                </ScrollViewer>
            </StackPanel>
        </Grid>

    </Grid>
</UserControl>

C#

using System.Collections.Generic;
using System.Windows;
using System.Windows.Controls;
using ESRI.ArcGIS.Client;
using ESRI.ArcGIS.Client.Tasks;

namespace ArcGISWPFSDK
{
    public partial class Identify : UserControl
    {
        private List<DataItem> _dataItems = null;

        public Identify()
        {
            InitializeComponent();
        }

        private void QueryPoint_MouseClick(object sender, ESRI.ArcGIS.Client.Map.MouseEventArgs e)
        {
            ESRI.ArcGIS.Client.Geometry.MapPoint clickPoint = e.MapPoint;

            ESRI.ArcGIS.Client.Tasks.IdentifyParameters identifyParams = new IdentifyParameters()
            {
                Geometry = clickPoint,
                MapExtent = MyMap.Extent,
                Width = (int)MyMap.ActualWidth,
                Height = (int)MyMap.ActualHeight,
                LayerOption = LayerOption.visible,
                SpatialReference = MyMap.SpatialReference
            };

            IdentifyTask identifyTask = new IdentifyTask("http://sampleserver1.arcgisonline.com/ArcGIS/rest/services/" +
                "Demographics/ESRI_Census_USA/MapServer");
            identifyTask.ExecuteCompleted += IdentifyTask_ExecuteCompleted;
            identifyTask.Failed += IdentifyTask_Failed;
            identifyTask.ExecuteAsync(identifyParams);

            GraphicsLayer graphicsLayer = MyMap.Layers["MyGraphicsLayer"] as GraphicsLayer;
            graphicsLayer.ClearGraphics();
            ESRI.ArcGIS.Client.Graphic graphic = new ESRI.ArcGIS.Client.Graphic()
            {
                Geometry = clickPoint,
                Symbol = LayoutRoot.Resources["DefaultPictureSymbol"] as ESRI.ArcGIS.Client.Symbols.Symbol
            };
            graphicsLayer.Graphics.Add(graphic);
        }

        public void ShowFeatures(List<IdentifyResult> results)
        {
            _dataItems = new List<DataItem>();

            if (results != null && results.Count > 0)
            {
                IdentifyComboBox.Items.Clear();
                foreach (IdentifyResult result in results)
                {
                    Graphic feature = result.Feature;
                    string title = result.Value.ToString() + " (" + result.LayerName + ")";
                    _dataItems.Add(new DataItem()
                    {
                        Title = title,
                        Data = feature.Attributes
                    });
                    IdentifyComboBox.Items.Add(title);
                }

                // Workaround for bug with ComboBox 
                IdentifyComboBox.UpdateLayout();

                IdentifyComboBox.SelectedIndex = 0;
            }
        }

        void cb_SelectionChanged(object sender, SelectionChangedEventArgs e)
        {
            int index = IdentifyComboBox.SelectedIndex;
            if (index > -1)
                IdentifyDetailsDataGrid.ItemsSource = _dataItems[index].Data;
        }

        private void IdentifyTask_ExecuteCompleted(object sender, IdentifyEventArgs args)
        {
            IdentifyDetailsDataGrid.ItemsSource = null;

            if (args.IdentifyResults != null && args.IdentifyResults.Count > 0)
            {
                IdentifyResultsPanel.Visibility = Visibility.Visible;

                ShowFeatures(args.IdentifyResults);
            }
            else
            {
                IdentifyComboBox.Items.Clear();
                IdentifyComboBox.UpdateLayout();

                IdentifyResultsPanel.Visibility = Visibility.Collapsed;
            }
        }

        public class DataItem
        {
            public string Title { get; set; }
            public IDictionary<string, object> Data { get; set; }
        }

        void IdentifyTask_Failed(object sender, TaskFailedEventArgs e)
        {
            MessageBox.Show("Identify failed. Error: " + e.Error);
        }
    }
}

VB.NET

Imports System.Collections.Generic
Imports System.Windows
Imports System.Windows.Controls
Imports ESRI.ArcGIS.Client
Imports ESRI.ArcGIS.Client.Tasks

Namespace ArcGISWPFSDK
    Partial Public Class Identify
        Inherits UserControl
        Private _dataItems As List(Of DataItem) = Nothing

        Public Sub New()
            InitializeComponent()
        End Sub

        Private Sub QueryPoint_MouseClick(sender As Object, e As ESRI.ArcGIS.Client.Map.MouseEventArgs)
            Dim clickPoint As ESRI.ArcGIS.Client.Geometry.MapPoint = e.MapPoint

            Dim identifyParams As ESRI.ArcGIS.Client.Tasks.IdentifyParameters = New IdentifyParameters() With { _
             .Geometry = clickPoint, _
             .MapExtent = MyMap.Extent, _
             .Width = CInt(Math.Truncate(MyMap.ActualWidth)), _
             .Height = CInt(Math.Truncate(MyMap.ActualHeight)), _
             .LayerOption = LayerOption.visible, _
             .SpatialReference = MyMap.SpatialReference _
            }

            Dim identifyTask As New IdentifyTask("http://sampleserver1.arcgisonline.com/ArcGIS/rest/services/" & "Demographics/ESRI_Census_USA/MapServer")
            AddHandler identifyTask.ExecuteCompleted, AddressOf IdentifyTask_ExecuteCompleted
            AddHandler identifyTask.Failed, AddressOf IdentifyTask_Failed
            identifyTask.ExecuteAsync(identifyParams)

            Dim graphicsLayer As GraphicsLayer = TryCast(MyMap.Layers("MyGraphicsLayer"), GraphicsLayer)
            graphicsLayer.ClearGraphics()
            Dim graphic As New ESRI.ArcGIS.Client.Graphic() With { _
             .Geometry = clickPoint, _
             .Symbol = TryCast(LayoutRoot.Resources("DefaultPictureSymbol"), ESRI.ArcGIS.Client.Symbols.Symbol) _
            }
            graphicsLayer.Graphics.Add(graphic)
        End Sub

        Public Sub ShowFeatures(results As List(Of IdentifyResult))
            _dataItems = New List(Of DataItem)()

            If results IsNot Nothing AndAlso results.Count > 0 Then
                IdentifyComboBox.Items.Clear()
                For Each result As IdentifyResult In results
                    Dim feature As Graphic = result.Feature
                    Dim title As String = result.Value.ToString() & " (" & result.LayerName & ")"
                    _dataItems.Add(New DataItem() With { _
                     .Title = title, _
                     .Data = feature.Attributes _
                    })
                    IdentifyComboBox.Items.Add(title)
                Next

                ' Workaround for bug with ComboBox 
                IdentifyComboBox.UpdateLayout()

                IdentifyComboBox.SelectedIndex = 0
            End If
        End Sub

        Private Sub cb_SelectionChanged(sender As Object, e As SelectionChangedEventArgs)
            Dim index As Integer = IdentifyComboBox.SelectedIndex
            If index > -1 Then
                IdentifyDetailsDataGrid.ItemsSource = _dataItems(index).Data
            End If
        End Sub

        Private Sub IdentifyTask_ExecuteCompleted(sender As Object, args As IdentifyEventArgs)
            IdentifyDetailsDataGrid.ItemsSource = Nothing

            If args.IdentifyResults IsNot Nothing AndAlso args.IdentifyResults.Count > 0 Then
                IdentifyResultsPanel.Visibility = Visibility.Visible

                ShowFeatures(args.IdentifyResults)
            Else
                IdentifyComboBox.Items.Clear()
                IdentifyComboBox.UpdateLayout()

                IdentifyResultsPanel.Visibility = Visibility.Collapsed
            End If
        End Sub

        Public Class DataItem
            Public Property Title() As String
                Get
                    Return m_Title
                End Get
                Set(value As String)
                    m_Title = Value
                End Set
            End Property
            Private m_Title As String
            Public Property Data() As IDictionary(Of String, Object)
                Get
                    Return m_Data
                End Get
                Set(value As IDictionary(Of String, Object))
                    m_Data = Value
                End Set
            End Property
            Private m_Data As IDictionary(Of String, Object)
        End Class

        Private Sub IdentifyTask_Failed(sender As Object, e As TaskFailedEventArgs)
            MessageBox.Show("Identify failed. Error: " & Convert.ToString(e.[Error]))
        End Sub
    End Class

End Namespace