On Demand FeatureLayer Online

This sample demonstrates selecting individual features in an ESRI.ArcGIS.Client FeatureLayer using OnDemand mode. Features that are in the current map extent are automatically selected as pan/zooms occur

XAML

<UserControl x:Class="ArcGISWPFSDK.FeatureLayerOnDemand"
    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">
        <Grid.Resources>
            <esri:SimpleRenderer x:Key="DefaultFillRenderer">
                <esri:SimpleRenderer.Symbol>
                    <esri:SimpleFillSymbol BorderBrush="Blue" Fill="#330000FF" />
                </esri:SimpleRenderer.Symbol>
            </esri:SimpleRenderer>
            <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="#FFE3E3E3">
            <esri:ArcGISTiledMapServiceLayer ID="BaseLayer" 
                Url="http://services.arcgisonline.com/ArcGIS/rest/services/World_Street_Map/MapServer" />
            <esri:FeatureLayer ID="CensusDemographics" 
                Url="http://sampleserver1.arcgisonline.com/ArcGIS/rest/services/Demographics/ESRI_Census_USA/MapServer/1"
                Mode="OnDemand" 
                Renderer="{StaticResource DefaultFillRenderer}" 
                OnDemandCacheSize="500" 
                OutFields="FIPS,POP2007">
                <esri:FeatureLayer.MapTip>
                    <Border CornerRadius="10" BorderBrush="Black" BorderThickness="2" Margin="0,0,15,15" Background="{StaticResource PanelGradient}" >
                            <StackPanel Margin="7">
                            <TextBlock Text="FIPS: " FontWeight="Bold" Foreground="White" />
                            <TextBlock Text="{Binding [FIPS]}" Foreground="White"  />
                            <StackPanel Orientation="Horizontal">
                                <TextBlock Text="Population: " FontWeight="Bold" Foreground="White" />
                                <TextBlock Text="{Binding [POP2007]}" Foreground="White" />
                            </StackPanel>
                        </StackPanel>
                    </Border>
                </esri:FeatureLayer.MapTip>
            </esri:FeatureLayer>
        </esri:Map>
        <Grid HorizontalAlignment="Left" VerticalAlignment="Top" Margin="10,10,10,0" >
            <Rectangle Fill="{StaticResource PanelGradient}" Stroke="Gray"  RadiusX="10" RadiusY="10" Margin="0,0,0,5">
                <Rectangle.Effect>
                    <DropShadowEffect/>
                </Rectangle.Effect>
            </Rectangle>
            <Rectangle Fill="#DDFFFFFF" Stroke="DarkGray" RadiusX="5" RadiusY="5" Margin="10,10,10,15" />
            <TextBlock x:Name="ResponseTextBlock" Text="The feature layer is in OnDemand mode. Only features within the current map extent are retrieved.  As the map extent changes, additional features are requested." 
                       Width="200" TextAlignment="Left" Margin="30,20,20,30" TextWrapping="Wrap" Foreground="Black" />
        </Grid>
    </Grid>
</UserControl>

C#

using System.Windows.Controls;

namespace ArcGISWPFSDK
{
    public partial class FeatureLayerOnDemand : UserControl
    {
        private static ESRI.ArcGIS.Client.Projection.WebMercator mercator = new ESRI.ArcGIS.Client.Projection.WebMercator();

        ESRI.ArcGIS.Client.Geometry.Envelope initialExtent = new ESRI.ArcGIS.Client.Geometry.Envelope(
                mercator.FromGeographic(new ESRI.ArcGIS.Client.Geometry.MapPoint(-117.190346717, 34.0514888762)) as ESRI.ArcGIS.Client.Geometry.MapPoint,
                mercator.FromGeographic(new ESRI.ArcGIS.Client.Geometry.MapPoint(-117.160305976, 34.072946548)) as ESRI.ArcGIS.Client.Geometry.MapPoint)
        {
            SpatialReference = new ESRI.ArcGIS.Client.Geometry.SpatialReference(102100)
        };

        public FeatureLayerOnDemand()
        {
            InitializeComponent();

            MyMap.Extent = initialExtent;
        }
    }
}

VB.NET

Imports System.Windows.Controls

Namespace ArcGISWPFSDK
    Partial Public Class FeatureLayerOnDemand
        Inherits UserControl
        Private Shared mercator As New ESRI.ArcGIS.Client.Projection.WebMercator()

        Private initialExtent As New ESRI.ArcGIS.Client.Geometry.Envelope(TryCast(mercator.FromGeographic(New ESRI.ArcGIS.Client.Geometry.MapPoint(-117.190346717, 34.0514888762)), ESRI.ArcGIS.Client.Geometry.MapPoint), TryCast(mercator.FromGeographic(New ESRI.ArcGIS.Client.Geometry.MapPoint(-117.160305976, 34.072946548)), ESRI.ArcGIS.Client.Geometry.MapPoint)) With { _
         .SpatialReference = New ESRI.ArcGIS.Client.Geometry.SpatialReference(102100) _
        }

        Public Sub New()
            InitializeComponent()

            MyMap.Extent = initialExtent
        End Sub
    End Class
End Namespace