Unique Value Renderer

This sample demonstrates the dynamic layers functionality of the ArcGIS Runtime by overriding the default renderers for the Cities, Highways and States feature layers (originally defined within ArcGIS for Desktop) with new UniqueValueRenderers defined via the ArcGIS Runtime client API. Crucially, this new rendering information is applied at the "server" level when rendering the map image. The user interface controls allow you to apply a new SimpleRenderer to each feature layer independently with the apppriate symbol type for the layer's geometry being used in each case: SimpleMarkerSymbol, SimpleLineSymbol or SimpleFillSymbol. The symbol properties are randomly generated by means of two utility functions which either create a random Color or a random enumeration value.

XAML

<UserControl x:Class="ArcGISWPFSDK.DynamicLayersUniqueValueRenderer"
             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>
        <Grid.Resources>
            <BooleanToVisibilityConverter x:Key="BooleanToVisibilityConverter"/>
            <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="_mapControl" Background="#FFE3E3E3">

        </esri:Map>
        <StackPanel Orientation="Vertical" Margin="10" HorizontalAlignment="Right" VerticalAlignment="Top">
            <Grid x:Name="DynamicLayersUiGrid" HorizontalAlignment="Right" VerticalAlignment="Top" Margin="0,5,5,0" Width="170">
                <Rectangle Fill="{StaticResource PanelGradient}" Stroke="Gray" Margin="0,0,0,5">
                    <Rectangle.Effect>
                        <DropShadowEffect/>
                    </Rectangle.Effect>
                </Rectangle>
                <StackPanel Orientation="Vertical" VerticalAlignment="Top">
                    <Canvas Margin="5,5,5,5" Height="105">
                        <Rectangle Height="105" Width="160" RadiusX="5" RadiusY="5" Fill="#DDFFFFFF" Stroke="DarkGray"/>
                        <StackPanel>
                            <TextBlock Text="Cities:" Foreground="Black" Margin="5,5,5,5"/>
                            <ComboBox x:Name="CitiesFieldsComboBox" SelectedIndex="0" Margin="5,0,5,5" Width="150">
                                <ComboBoxItem>CLASS</ComboBoxItem>
                                <ComboBoxItem>ST</ComboBoxItem>
                                <ComboBoxItem>CAPITAL</ComboBoxItem>
                            </ComboBox>
                            <Button x:Name="ChangeCitiesRendererButton" Content="Change Renderer" Foreground="Black" 
                            Margin="5,0,5,5" Width="150" Click="ChangeCitiesRendererButton_Click" />
                            <Button x:Name="ResetCitiesRendererButton" Content="Reset Renderer" Foreground="Black" 
                            Margin="5,0,5,5" Width="150" Click="ResetCitiesRendererButton_Click" />
                        </StackPanel>
                    </Canvas>
                    <Canvas Margin="5,0,5,5" Height="105">
                        <Rectangle Height="105" Width="160" RadiusX="5" RadiusY="5" Fill="#DDFFFFFF" Stroke="DarkGray"/>
                        <StackPanel>
                            <TextBlock Text="Highways:" Foreground="Black" Margin="5,5,5,5"/>
                            <ComboBox x:Name="HighwaysFieldsComboBox" SelectedIndex="0" Margin="5,0,5,5" Width="150">
                                <ComboBoxItem>TYPE</ComboBoxItem>
                                <ComboBoxItem>ADMN_CLASS</ComboBoxItem>
                                <ComboBoxItem>ROUTE</ComboBoxItem>
                            </ComboBox>
                            <Button x:Name="ChangeHighwaysRendererButton" Content="Change Renderer" Foreground="Black" 
                             Margin="5,0,5,5" Width="150" Click="ChangeHighwaysRendererButton_Click" />
                            <Button x:Name="ResetHighwaysRendererButton" Content="Reset Renderer" Foreground="Black" 
                            Margin="5,0,5,5" Width="150" Click="ResetHighwaysRendererButton_Click" />
                        </StackPanel>
                    </Canvas>
                    <Canvas Margin="5,0,5,5" Height="105">
                        <Rectangle Height="105" Width="160" RadiusX="5" RadiusY="5" Fill="#DDFFFFFF" Stroke="DarkGray"/>
                        <StackPanel>
                            <TextBlock Text="States:" Foreground="Black" Margin="5,5,5,5"/>
                            <ComboBox x:Name="StatesFieldsComboBox" SelectedIndex="0" Margin="5,0,5,5" Width="150">
                                <ComboBoxItem>STATE_NAME</ComboBoxItem>
                                <ComboBoxItem>SUB_REGION</ComboBoxItem>
                            </ComboBox>
                            <Button x:Name="ChangeStatesRendererButton" Content="Change Renderer" Foreground="Black" 
                            Margin="5,0,5,5" Width="150" Click="ChangeStatesRendererButton_Click" />
                            <Button x:Name="ResetStatesRendererButton" Content="Reset Renderer" Foreground="Black" 
                            Margin="5,0,5,5" Width="150" Click="ResetStatesRendererButton_Click" />
                        </StackPanel>
                    </Canvas>
                    <Canvas Margin="5,0,5,5" Height="35">
                        <Rectangle Height="30" Width="160" RadiusX="5" RadiusY="5" Fill="#DDFFFFFF" Stroke="DarkGray"/>
                        <StackPanel>
                            <Button x:Name="ResetAllRenderersButton" Content="Reset All Renderers" Foreground="Black" 
                            Margin="5,5,5,5" Width="150" Click="ResetAllRenderersButton_Click" />
                        </StackPanel>
                    </Canvas>
                </StackPanel>
            </Grid>
        </StackPanel>
        <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;
using System.Collections.Generic;
using System.Linq;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Media;
using ESRI.ArcGIS.Client.Local;
using ESRI.ArcGIS.Client;
using ESRI.ArcGIS.Client.Tasks;
using System.ComponentModel;

namespace ArcGISWPFSDK
{
    public partial class DynamicLayersUniqueValueRenderer : 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"));
                }
            }
        }    
    
        // Member variable for the dynamic map service layer
        ArcGISLocalDynamicMapServiceLayer _arcGISLocalDynamicMapServiceLayer;

        // Member variable for the random number generator to create symbol sizes, line widths, etc.
        Random _random = new Random();

        // Member variables representing the LayerDrawingOptions definition for each layer. 
        // Allows them to be easily removed from the layer's LayerDrawingOptions collection.
        LayerDrawingOptions _citiesLayerDrawingOptions;
        LayerDrawingOptions _highwaysLayerDrawingOptions;
        LayerDrawingOptions _statesLayerDrawingOptions;

        public DynamicLayersUniqueValueRenderer()
        {
            InitializeComponent();

            // Disable the UI Grid until the ArcGISDynamicMapServiceLayer has initialized.
            DynamicLayersUiGrid.IsEnabled = false;

            // Create a new local map service from an MPK and enable the 
            // Dynamic Layers capability
            LocalMapService localMapService = new LocalMapService()
            {
                Path = @"..\Data\DynamicLayers\USA.mpk",
                EnableDynamicLayers = true
            };

            // Start the local map service and once initialized
            localMapService.StartAsync((mapService) =>
            {
                // create a new local dynamic map service layer based on the local map service 
                _arcGISLocalDynamicMapServiceLayer = new ArcGISLocalDynamicMapServiceLayer(localMapService)
                {
                    ID = "_arcGISLocalDynamicMapServiceLayer",
                    ImageFormat = ArcGISDynamicMapServiceLayer.RestImageFormat.PNG32,
                };

                // Set up an event handler for the layer initialized event
                _arcGISLocalDynamicMapServiceLayer.Initialized += (s, e) =>
                {
                    //Enable the UI once the layer has initialized
                    DynamicLayersUiGrid.IsEnabled = true;
                    DataContext = this;
                    IsBusy = false;
                };

                // Add the layer to the map
                _mapControl.Layers.Add(_arcGISLocalDynamicMapServiceLayer);
            });
        }

        private void ChangeCitiesRendererButton_Click(object sender, RoutedEventArgs e)
        {
            // If there is already an instance of the Cities LayerDrawOptions definition 
            // remove it from the layer's LayerDrawingOptions collection.
            if (_citiesLayerDrawingOptions != null)
                ResetRenderer(_citiesLayerDrawingOptions, false);

            // Create a new Layer Drawing Options object which will define the new
            // renderer for a specific layer in the underlying local map service
            _citiesLayerDrawingOptions = new LayerDrawingOptions();

            // Set the ID of the map layer in the local map service
            _citiesLayerDrawingOptions.LayerID = 0;

            // Get the selected Field combo box item
            System.Windows.Controls.ComboBoxItem selectedItem =
                ((System.Windows.Controls.ComboBoxItem)CitiesFieldsComboBox.SelectedItem);

            // Create a new simple renderer and set the renderer property
            // on the layer drawing options object
            _citiesLayerDrawingOptions.Renderer = GetUniqueValueRenderer("Cities", selectedItem.Content.ToString());

            // Create a new layer drawing options collection and set the layer drawing options
            // property on the local dynamic map service layer
            if (_arcGISLocalDynamicMapServiceLayer.LayerDrawingOptions == null)
                _arcGISLocalDynamicMapServiceLayer.LayerDrawingOptions = new LayerDrawingOptionsCollection() { _citiesLayerDrawingOptions };
            else
                _arcGISLocalDynamicMapServiceLayer.LayerDrawingOptions.Add(_citiesLayerDrawingOptions);
            // Refresh the layer
            _arcGISLocalDynamicMapServiceLayer.Refresh();
        }


        private void ChangeHighwaysRendererButton_Click(object sender, RoutedEventArgs e)
        {
            // If there is already an instance of the Cities LayerDrawOptions definition 
            // remove it from the layer's LayerDrawingOptions collection.
            if (_highwaysLayerDrawingOptions != null)
                ResetRenderer(_highwaysLayerDrawingOptions, false);

            // Create a new Layer Drawing Options object which will define the new
            // renderer for a specific layer in the underlying local map service
            _highwaysLayerDrawingOptions = new LayerDrawingOptions();

            // Set the ID of the map layer in the local map service
            _highwaysLayerDrawingOptions.LayerID = 1;

            // Get the selected Field combo box item
            System.Windows.Controls.ComboBoxItem selectedItem =
                ((System.Windows.Controls.ComboBoxItem)HighwaysFieldsComboBox.SelectedItem);

            // Create a new simple renderer and set the renderer property
            // on the layer drawing options object
            _highwaysLayerDrawingOptions.Renderer = GetUniqueValueRenderer("Highways", selectedItem.Content.ToString());

            // Create a new layer drawing options collection and set the layer drawing options
            // property on the local dynamic map service layer
            if (_arcGISLocalDynamicMapServiceLayer.LayerDrawingOptions == null)
                _arcGISLocalDynamicMapServiceLayer.LayerDrawingOptions = new LayerDrawingOptionsCollection() { _highwaysLayerDrawingOptions };
            else
                _arcGISLocalDynamicMapServiceLayer.LayerDrawingOptions.Add(_highwaysLayerDrawingOptions);
            // Refresh the layer
            _arcGISLocalDynamicMapServiceLayer.Refresh();
        }

        private void ChangeStatesRendererButton_Click(object sender, RoutedEventArgs e)
        {
            // If there is already an instance of the Cities LayerDrawOptions definition 
            // remove it from the layer's LayerDrawingOptions collection.
            if (_statesLayerDrawingOptions != null)
                ResetRenderer(_statesLayerDrawingOptions, false);

            // Create a new Layer Drawing Options object which will define the new
            // renderer for a specific layer in the underlying local map service
            _statesLayerDrawingOptions = new LayerDrawingOptions();

            // Set the ID of the map layer in the local map service
            _statesLayerDrawingOptions.LayerID = 2;

            // Get the selected Field combo box item
            System.Windows.Controls.ComboBoxItem selectedItem =
                ((System.Windows.Controls.ComboBoxItem)StatesFieldsComboBox.SelectedItem);

            // Create a new simple renderer and set the renderer property
            // on the layer drawing options object
            _statesLayerDrawingOptions.Renderer = GetUniqueValueRenderer("States", selectedItem.Content.ToString());

            // Create a new layer drawing options collection and set the layer drawing options
            // property on the local dynamic map service layer
            if (_arcGISLocalDynamicMapServiceLayer.LayerDrawingOptions == null)
                _arcGISLocalDynamicMapServiceLayer.LayerDrawingOptions = new LayerDrawingOptionsCollection() { _statesLayerDrawingOptions };
            else
                _arcGISLocalDynamicMapServiceLayer.LayerDrawingOptions.Add(_statesLayerDrawingOptions);

            //Refresh the map to initiate a new server request
            _arcGISLocalDynamicMapServiceLayer.Refresh();
        }

        private UniqueValueRenderer GetUniqueValueRenderer(string layerName, string attributeField)
        {
            UniqueValueRenderer uniqueValueRenderer = null;
            LayerInfo layerInfo = _arcGISLocalDynamicMapServiceLayer.Layers.First(l => l.Name == layerName);
            var generateDataClassesTask = new GenerateRendererTask(_arcGISLocalDynamicMapServiceLayer.Url + "/" + layerInfo.ID);

            var generateDataClassesParameters = new GenerateRendererParameters
            {
                ClassificationDefinition = new UniqueValueDefinition
                {
                    ColorRamps = new System.Collections.ObjectModel.ObservableCollection<ColorRamp>()
                    { new ColorRamp()
                        {

                        Algorithm = Algorithm.CIELabAlgorithm,
                        From = GetRandomColor(),
                        To = GetRandomColor()
                        }
                    },
                    Fields = new List<string>() { attributeField }
                }
            };

            try
            {
                GenerateRendererResult generateDataClassesResult = generateDataClassesTask.Execute(generateDataClassesParameters);
                uniqueValueRenderer = generateDataClassesResult.Renderer as UniqueValueRenderer;
            }
            catch (Exception ex)
            {
                // Handle any exceptions
                var errorMessage = ex.Message;
            }

            return uniqueValueRenderer;
        }

        private void ResetCitiesRendererButton_Click(object sender, RoutedEventArgs e)
        {
            // Remove the Cities LayerDrawOptions definition from the layer's LayerDrawingOptions collection
            // and refresh the map.
            ResetRenderer(_citiesLayerDrawingOptions, true);
        }

        private void ResetHighwaysRendererButton_Click(object sender, RoutedEventArgs e)
        {
            // Remove the Cities LayerDrawOptions definition from the layer's LayerDrawingOptions collection
            // and refresh the map.
            ResetRenderer(_highwaysLayerDrawingOptions, true);
        }

        private void ResetStatesRendererButton_Click(object sender, RoutedEventArgs e)
        {
            // Remove the Cities LayerDrawOptions definition from the layer's LayerDrawingOptions collection
            // and refresh the map.
            ResetRenderer(_statesLayerDrawingOptions, true);
        }

        private void ResetAllRenderersButton_Click(object sender, RoutedEventArgs e)
        {
            // Exit if there are no items in the layer's LayerDrawingOptions collection
            if (_arcGISLocalDynamicMapServiceLayer.LayerDrawingOptions == null || _arcGISLocalDynamicMapServiceLayer.LayerDrawingOptions.Count == 0)
                return;

            // Clear the layer's LayerDrawingOptions collection
            _arcGISLocalDynamicMapServiceLayer.LayerDrawingOptions.Clear();

            //Refresh the map to initiate a new server request
            _arcGISLocalDynamicMapServiceLayer.Refresh();
        }

        public void ResetRenderer(LayerDrawingOptions layerDrawingOptions, bool refreshMap)
        {
            if (_arcGISLocalDynamicMapServiceLayer.LayerDrawingOptions == null || _arcGISLocalDynamicMapServiceLayer.LayerDrawingOptions.Count == 0)
                return;

            if (_arcGISLocalDynamicMapServiceLayer.LayerDrawingOptions.Contains(layerDrawingOptions))
            {
                _arcGISLocalDynamicMapServiceLayer.LayerDrawingOptions.Remove(layerDrawingOptions);

                if (refreshMap)
                    _arcGISLocalDynamicMapServiceLayer.Refresh();
            }
        }

        // Utility function: Generate a random System.Windows.Media.Color
        private Color GetRandomColor()
        {
            var colorBytes = new byte[3];
            _random.NextBytes(colorBytes);
            Color randomColor = Color.FromRgb(colorBytes[0], colorBytes[1], colorBytes[2]);
            return randomColor;
        }
    }
}

VB.NET

Imports System.Collections.Generic
Imports System.Linq
Imports System.Windows
Imports System.Windows.Controls
Imports System.Windows.Media
Imports ESRI.ArcGIS.Client.Local
Imports ESRI.ArcGIS.Client
Imports ESRI.ArcGIS.Client.Tasks
Imports System.ComponentModel

Namespace ArcGISWPFSDK
    Partial Public Class DynamicLayersUniqueValueRenderer
        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
        ' Member variable for the dynamic map service layer
        Private _arcGISLocalDynamicMapServiceLayer As ArcGISLocalDynamicMapServiceLayer

        ' Member variable for the random number generator to create symbol sizes, line widths, etc.
        Private _random As New Random()

        ' Member variables representing the LayerDrawingOptions definition for each layer. 
        ' Allows them to be easily removed from the layer's LayerDrawingOptions collection.
        Private _citiesLayerDrawingOptions As LayerDrawingOptions
        Private _highwaysLayerDrawingOptions As LayerDrawingOptions
        Private _statesLayerDrawingOptions As LayerDrawingOptions

        Public Sub New()
            InitializeComponent()

            ' Disable the UI Grid until the ArcGISDynamicMapServiceLayer has initialized.
            DynamicLayersUiGrid.IsEnabled = False

            ' Create a new local map service from an MPK and enable the 
            ' Dynamic Layers capability
            Dim localMapService As New LocalMapService() With { _
             .Path = "..\Data\DynamicLayers\USA.mpk", _
             .EnableDynamicLayers = True _
            }

            ' Start the local map service and once initialized
            localMapService.StartAsync(Function(mapService)
                                           ' create a new local dynamic map service layer based on the local map service 
                                           _arcGISLocalDynamicMapServiceLayer = New ArcGISLocalDynamicMapServiceLayer(localMapService) With { _
                                            .ID = "_arcGISLocalDynamicMapServiceLayer", _
                                            .ImageFormat = ArcGISDynamicMapServiceLayer.RestImageFormat.PNG32 _
                                           }

                                           ' Set up an event handler for the layer initialized event
                                           AddHandler _arcGISLocalDynamicMapServiceLayer.Initialized, Function(s, e)
                                                                                                          'Enable the UI once the layer has initialized
                                                                                                          DynamicLayersUiGrid.IsEnabled = True
                                                                                                          DataContext = Me
                                                                                                          IsBusy = False
                                                                                                      End Function

                                           ' Add the layer to the map
                                           _mapControl.Layers.Add(_arcGISLocalDynamicMapServiceLayer)

                                       End Function)
        End Sub

        Private Sub ChangeCitiesRendererButton_Click(sender As Object, e As RoutedEventArgs)
            ' If there is already an instance of the Cities LayerDrawOptions definition 
            ' remove it from the layer's LayerDrawingOptions collection.
            If _citiesLayerDrawingOptions IsNot Nothing Then
                ResetRenderer(_citiesLayerDrawingOptions, False)
            End If

            ' Create a new Layer Drawing Options object which will define the new
            ' renderer for a specific layer in the underlying local map service
            _citiesLayerDrawingOptions = New LayerDrawingOptions()

            ' Set the ID of the map layer in the local map service
            _citiesLayerDrawingOptions.LayerID = 0

            ' Get the selected Field combo box item
            Dim selectedItem As System.Windows.Controls.ComboBoxItem = DirectCast(CitiesFieldsComboBox.SelectedItem, System.Windows.Controls.ComboBoxItem)

            ' Create a new simple renderer and set the renderer property
            ' on the layer drawing options object
            _citiesLayerDrawingOptions.Renderer = GetUniqueValueRenderer("Cities", selectedItem.Content.ToString())

            ' Create a new layer drawing options collection and set the layer drawing options
            ' property on the local dynamic map service layer
            If _arcGISLocalDynamicMapServiceLayer.LayerDrawingOptions Is Nothing Then
                _arcGISLocalDynamicMapServiceLayer.LayerDrawingOptions = New LayerDrawingOptionsCollection() From { _
                 _citiesLayerDrawingOptions _
                }
            Else
                _arcGISLocalDynamicMapServiceLayer.LayerDrawingOptions.Add(_citiesLayerDrawingOptions)
            End If
            ' Refresh the layer
            _arcGISLocalDynamicMapServiceLayer.Refresh()
        End Sub


        Private Sub ChangeHighwaysRendererButton_Click(sender As Object, e As RoutedEventArgs)
            ' If there is already an instance of the Cities LayerDrawOptions definition 
            ' remove it from the layer's LayerDrawingOptions collection.
            If _highwaysLayerDrawingOptions IsNot Nothing Then
                ResetRenderer(_highwaysLayerDrawingOptions, False)
            End If

            ' Create a new Layer Drawing Options object which will define the new
            ' renderer for a specific layer in the underlying local map service
            _highwaysLayerDrawingOptions = New LayerDrawingOptions()

            ' Set the ID of the map layer in the local map service
            _highwaysLayerDrawingOptions.LayerID = 1

            ' Get the selected Field combo box item
            Dim selectedItem As System.Windows.Controls.ComboBoxItem = DirectCast(HighwaysFieldsComboBox.SelectedItem, System.Windows.Controls.ComboBoxItem)

            ' Create a new simple renderer and set the renderer property
            ' on the layer drawing options object
            _highwaysLayerDrawingOptions.Renderer = GetUniqueValueRenderer("Highways", selectedItem.Content.ToString())

            ' Create a new layer drawing options collection and set the layer drawing options
            ' property on the local dynamic map service layer
            If _arcGISLocalDynamicMapServiceLayer.LayerDrawingOptions Is Nothing Then
                _arcGISLocalDynamicMapServiceLayer.LayerDrawingOptions = New LayerDrawingOptionsCollection() From { _
                 _highwaysLayerDrawingOptions _
                }
            Else
                _arcGISLocalDynamicMapServiceLayer.LayerDrawingOptions.Add(_highwaysLayerDrawingOptions)
            End If
            ' Refresh the layer
            _arcGISLocalDynamicMapServiceLayer.Refresh()
        End Sub

        Private Sub ChangeStatesRendererButton_Click(sender As Object, e As RoutedEventArgs)
            ' If there is already an instance of the Cities LayerDrawOptions definition 
            ' remove it from the layer's LayerDrawingOptions collection.
            If _statesLayerDrawingOptions IsNot Nothing Then
                ResetRenderer(_statesLayerDrawingOptions, False)
            End If

            ' Create a new Layer Drawing Options object which will define the new
            ' renderer for a specific layer in the underlying local map service
            _statesLayerDrawingOptions = New LayerDrawingOptions()

            ' Set the ID of the map layer in the local map service
            _statesLayerDrawingOptions.LayerID = 2

            ' Get the selected Field combo box item
            Dim selectedItem As System.Windows.Controls.ComboBoxItem = DirectCast(StatesFieldsComboBox.SelectedItem, System.Windows.Controls.ComboBoxItem)

            ' Create a new simple renderer and set the renderer property
            ' on the layer drawing options object
            _statesLayerDrawingOptions.Renderer = GetUniqueValueRenderer("States", selectedItem.Content.ToString())

            ' Create a new layer drawing options collection and set the layer drawing options
            ' property on the local dynamic map service layer
            If _arcGISLocalDynamicMapServiceLayer.LayerDrawingOptions Is Nothing Then
                _arcGISLocalDynamicMapServiceLayer.LayerDrawingOptions = New LayerDrawingOptionsCollection() From { _
                 _statesLayerDrawingOptions _
                }
            Else
                _arcGISLocalDynamicMapServiceLayer.LayerDrawingOptions.Add(_statesLayerDrawingOptions)
            End If

            'Refresh the map to initiate a new server request
            _arcGISLocalDynamicMapServiceLayer.Refresh()
        End Sub

        Private Function GetUniqueValueRenderer(layerName As String, attributeField As String) As UniqueValueRenderer
            Dim uniqueValueRenderer As UniqueValueRenderer = Nothing
            Dim layerInfo As LayerInfo = _arcGISLocalDynamicMapServiceLayer.Layers.First(Function(l) l.Name = layerName)
            Dim generateDataClassesTask = New GenerateRendererTask(_arcGISLocalDynamicMapServiceLayer.Url & "/" & layerInfo.ID)


            Dim generateDataClassesParameters = New GenerateRendererParameters() With { _
             .ClassificationDefinition = New UniqueValueDefinition() With { _
              .ColorRamps = New System.Collections.ObjectModel.ObservableCollection(Of ColorRamp)() From { _
               New ColorRamp() With { _
                .Algorithm = Algorithm.CIELabAlgorithm, _
                .From = GetRandomColor(), _
                .[To] = GetRandomColor() _
               } _
              }, _
              .Fields = New List(Of String)() From { _
               attributeField _
              } _
             } _
            }

            Try
                Dim generateDataClassesResult As GenerateRendererResult = generateDataClassesTask.Execute(generateDataClassesParameters)
                uniqueValueRenderer = TryCast(generateDataClassesResult.Renderer, UniqueValueRenderer)
            Catch ex As Exception
                ' Handle any exceptions
                Dim errorMessage = ex.Message
            End Try

            Return uniqueValueRenderer
        End Function

        Private Sub ResetCitiesRendererButton_Click(sender As Object, e As RoutedEventArgs)
            ' Remove the Cities LayerDrawOptions definition from the layer's LayerDrawingOptions collection
            ' and refresh the map.
            ResetRenderer(_citiesLayerDrawingOptions, True)
        End Sub

        Private Sub ResetHighwaysRendererButton_Click(sender As Object, e As RoutedEventArgs)
            ' Remove the Cities LayerDrawOptions definition from the layer's LayerDrawingOptions collection
            ' and refresh the map.
            ResetRenderer(_highwaysLayerDrawingOptions, True)
        End Sub

        Private Sub ResetStatesRendererButton_Click(sender As Object, e As RoutedEventArgs)
            ' Remove the Cities LayerDrawOptions definition from the layer's LayerDrawingOptions collection
            ' and refresh the map.
            ResetRenderer(_statesLayerDrawingOptions, True)
        End Sub

        Private Sub ResetAllRenderersButton_Click(sender As Object, e As RoutedEventArgs)
            ' Exit if there are no items in the layer's LayerDrawingOptions collection
            If _arcGISLocalDynamicMapServiceLayer.LayerDrawingOptions Is Nothing OrElse _arcGISLocalDynamicMapServiceLayer.LayerDrawingOptions.Count = 0 Then
                Return
            End If

            ' Clear the layer's LayerDrawingOptions collection
            _arcGISLocalDynamicMapServiceLayer.LayerDrawingOptions.Clear()

            'Refresh the map to initiate a new server request
            _arcGISLocalDynamicMapServiceLayer.Refresh()
        End Sub

        Public Sub ResetRenderer(layerDrawingOptions As LayerDrawingOptions, refreshMap As Boolean)
            If _arcGISLocalDynamicMapServiceLayer.LayerDrawingOptions Is Nothing OrElse _arcGISLocalDynamicMapServiceLayer.LayerDrawingOptions.Count = 0 Then
                Return
            End If

            If _arcGISLocalDynamicMapServiceLayer.LayerDrawingOptions.Contains(layerDrawingOptions) Then
                _arcGISLocalDynamicMapServiceLayer.LayerDrawingOptions.Remove(layerDrawingOptions)

                If refreshMap Then
                    _arcGISLocalDynamicMapServiceLayer.Refresh()
                End If
            End If
        End Sub

        ' Utility function: Generate a random System.Windows.Media.Color
        Private Function GetRandomColor() As Color
            Dim colorBytes = New Byte(2) {}
            _random.NextBytes(colorBytes)
            Dim randomColor As Color = Color.FromRgb(colorBytes(0), colorBytes(1), colorBytes(2))
            Return randomColor
        End Function
    End Class
End Namespace