Public Property Radius As Integer

public int Radius {get; set;}

<Grid x:Name="LayoutRoot" >
  
  <!-- Add a Map Control to the application. Set the Extent the NorthCentral California. -->
  <esri:Map x:Name="Map1" WrapAround="True" HorizontalAlignment="Left" VerticalAlignment="Top" 
        Margin="12,158,0,0" Height="300" Width="400" Extent="-13817069,4368389,-13228599,4809741"
        IsLogoVisible="False">
  
    <!-- Add a backdrop FeatureLayer for reference. It is the polygon boundary for the state of California. -->
    <esri:FeatureLayer ID="CA" IgnoreServiceScaleRange="True" Where="ST_ABBREV = 'CA'"
    Url="http://server.arcgisonline.com/ArcGIS/rest/services/Demographics/USA_Unemployment_Rate/MapServer/4"/>
    
    <!-- 
    Add a FeatureLayer that has the Initialized Event wired up for code-behind. The Initialized Event will set up
    the starting tick value for the Slider that matches the FeatureLayer.FlareClusterer.Radius.
    The FeatureLayer is based upon MapPoint Graphics that represent cities in California. 
    -->
    <esri:FeatureLayer ID="California_Cities" IgnoreServiceScaleRange="True" Where="STATE_NAME='California'"
    Url="http://sampleserver1.arcgisonline.com/ArcGIS/rest/services/Specialty/ESRI_StatesCitiesRivers_USA/MapServer/0"
    Initialized="FeatureLayer_Initialized">
    
      <!--
      Add a FlareClusterer to the FeatureLayer. Supply default values for the .Radius, .FlareBackground, 
      and FlareForeground Prperties.
      -->
      <esri:FeatureLayer.Clusterer>
        <esri:FlareClusterer FlareBackground="Yellow" FlareForeground="Green" Radius="20">
        
          <!--
          Add a custom FlareClusterer.Gradient that ramps colors between White, Red, and Black.
          -->
          <esri:FlareClusterer.Gradient>
            <LinearGradientBrush MappingMode="RelativeToBoundingBox" >
              <GradientStop Color="White" Offset="0.0" />
              <GradientStop Color="Red" Offset="0.5" />
              <GradientStop Color="Black" Offset="1.0" />
            </LinearGradientBrush>
          </esri:FlareClusterer.Gradient>
        </esri:FlareClusterer>
      </esri:FeatureLayer.Clusterer>
    </esri:FeatureLayer>
    
  </esri:Map>
  
  <!-- Add controls for changing the FlareClusterer.Radius of the California cities FeatureLayer. -->
  <sdk:Label Height="22" HorizontalAlignment="Left" Margin="12,103,0,0" Name="Label3" VerticalAlignment="Top" Width="134" 
       Content="FlareClusterer.Radius:"/>
  <Slider Height="23" HorizontalAlignment="Left" Margin="12,129,0,0" Name="Slider1" VerticalAlignment="Top" Width="106" 
          Minimum="1" Maximum="100" ValueChanged="Slider1_ValueChanged" />
  <TextBlock Height="23" HorizontalAlignment="Left" Margin="134,129,0,0" Name="TextBlock_SliderValue" VerticalAlignment="Top" />
  
  <!-- Provide the instructions on how to use the sample code. -->
  <TextBlock Height="97" HorizontalAlignment="Left" Name="TextBlock1" VerticalAlignment="Top" Width="427" 
  TextWrapping="Wrap" Text="Move the slider to see how changing the FlareClusterer.Radius impacts the 
  visual appearance of the FlareClusterer." />
  
</Grid>

private void Slider1_ValueChanged(object sender, System.Windows.RoutedPropertyChangedEventArgs<System.Double> e)
{
  // Ensure that the Slider has been initialized before trying to use other UI Controls.
  if (Slider1 != null)
  {
    // Display the Slider tick value in a TextBlock. It will adjust as the user moves the slider.
    TextBlock_SliderValue.Text = Convert.ToInt32(Slider1.Value).ToString();
    
    // Get the California cities FeatureLayer from the Map.
    ESRI.ArcGIS.Client.FeatureLayer theFeatureLayer = (ESRI.ArcGIS.Client.FeatureLayer)Map1.Layers["California_Cities"];
    
    // Get the FlareClusterer from the FeatureLayer.
    ESRI.ArcGIS.Client.FlareClusterer theFlareClusterer = (ESRI.ArcGIS.Client.FlareClusterer)theFeatureLayer.Clusterer;
    
    // Set the FlareClusterer.Radius to the TextBlock value (this is what the user specified on the Slider).
    theFlareClusterer.Radius = Convert.ToInt32(TextBlock_SliderValue.Text);
    
    // Refresh the Graphics in the FeatureLayer.
    theFeatureLayer.Refresh();
  }
}
            
private void FeatureLayer_Initialized(object sender, System.EventArgs e)
{
  // Ensure that the Slider has been initialized before trying to use other UI Controls.
  if (Slider1 != null)
  {
    // Get the California cities FeatureLayer from the Map.
    ESRI.ArcGIS.Client.FeatureLayer theFeatureLayer = (ESRI.ArcGIS.Client.FeatureLayer)sender;
    
    // Get the FlareClusterer from the FeatureLayer.
    ESRI.ArcGIS.Client.FlareClusterer theFlareClusterer = (ESRI.ArcGIS.Client.FlareClusterer)theFeatureLayer.Clusterer;
    
    // Set the initial Slider's tick value to that of the FlareClusterer.Radius that was set in XAML.
    Slider1.Value = theFlareClusterer.Radius;
  }
}

Private Sub Slider1_ValueChanged(sender As System.Object, e As System.Windows.RoutedPropertyChangedEventArgs(Of System.Double))
  
  ' Ensure that the Slider has been initialized before trying to use other UI Controls.
  If Slider1 IsNot Nothing Then
    
    ' Display the Slider tick value in a TextBlock. It will adjust as the user moves the slider.
    TextBlock_SliderValue.Text = CInt(Slider1.Value)
    
    ' Get the California cities FeatureLayer from the Map.
    Dim theFeatureLayer As ESRI.ArcGIS.Client.FeatureLayer = Map1.Layers("California_Cities")
    
    ' Get the FlareClusterer from the FeatureLayer.
    Dim theFlareClusterer As ESRI.ArcGIS.Client.FlareClusterer = theFeatureLayer.Clusterer
    
    ' Set the FlareClusterer.Radius to the TextBlock value (this is what the user specified on the Slider).
    theFlareClusterer.Radius = CInt(TextBlock_SliderValue.Text)
    
    ' Refresh the Graphics in the FeatureLayer.
    theFeatureLayer.Refresh()
    
  End If
  
End Sub
            
Private Sub FeatureLayer_Initialized(sender As System.Object, e As System.EventArgs)
  
  ' Ensure that the Slider has been initialized before trying to use other UI Controls.
  If Slider1 IsNot Nothing Then
    
    ' Get the California cities FeatureLayer from the Map.
    Dim theFeatureLayer As ESRI.ArcGIS.Client.FeatureLayer = sender
    
    ' Get the FlareClusterer from the FeatureLayer.
    Dim theFlareClusterer As ESRI.ArcGIS.Client.FlareClusterer = theFeatureLayer.Clusterer
    
    ' Set the initial Slider's tick value to that of the FlareClusterer.Radius that was set in XAML.
  Slider1.Value = theFlareClusterer.Radius
  
  End If
  
End Sub