Public Shared Property DefaultCachePolicy As RequestCachePolicy

public static RequestCachePolicy DefaultCachePolicy {get; set;}

<Grid>
  
  <!-- Add a Map Control -->
  <esri:Map WrapAround="True" x:Name="MyMap" Margin="360,94,10,10">
    
    <!-- Add an ArcGISTiledMapServiceLayer.-->
    <esri:ArcGISTiledMapServiceLayer ID="MyLayer" Url="http://sampleserver6.arcgisonline.com/arcgis/rest/services/SampleWorldCities/MapServer" />
    
  </esri:Map>
  
  <!-- Add a ComboBox and a Button to the application. -->
  <ComboBox x:Name="RequestPolicyLevel"  SelectionChanged="RequestPolicyLevel_SelectionChanged_1" Margin="14,156,446,374"/>
  <Button Content="Query" Click="Button_Click_1" Margin="13,117,447,421" />
  
  <!-- Provide the instructions on how to use the sample code. -->
  <TextBlock Height="94" HorizontalAlignment="Left" Name="TextBlock1" VerticalAlignment="Top" Width="625" TextWrapping="Wrap" 
   Text="Change the options for the various System.Net.Cache.RequestCacheLevel Enumerations and then click the button. 
   View the Headers of the web traffic in an internet monitoring application (like Fiddler) to see the various Cached 
   policys being used." Margin="0,10,-108,0" />
   
</Grid>

public MainWindow()
{
  InitializeComponent();
  
  // Add the different System.Net.Cache.RequestCacheLevel to the ComboBox.
  RequestPolicyLevel.ItemsSource = new System.Net.Cache.RequestCacheLevel[] 
  { 
    System.Net.Cache.RequestCacheLevel.BypassCache, 
    System.Net.Cache.RequestCacheLevel.CacheIfAvailable, 
    System.Net.Cache.RequestCacheLevel.CacheOnly, 
    System.Net.Cache.RequestCacheLevel.Default, 
    System.Net.Cache.RequestCacheLevel.NoCacheNoStore, 
    System.Net.Cache.RequestCacheLevel.Reload, 
    System.Net.Cache.RequestCacheLevel.Revalidate 
  };
  
  // Set the default item to appear in the ComboBox when the application loads.
  RequestPolicyLevel.SelectedItem = System.Net.Cache.RequestCacheLevel.Default;
}
            
private void RequestPolicyLevel_SelectionChanged_1(object sender, SelectionChangedEventArgs e)
{
  // Get the System.Net.Cache.RequestCacheLevel from the selected ComboxBox selection.
  System.Net.Cache.RequestCacheLevel myRequestCacheLevel = (System.Net.Cache.RequestCacheLevel)((sender as ComboBox).SelectedItem);
  
  // Set the Shared/static ArcGISWebClient.DefaultCachePolicy Property. This will affect all ArcGIS Runtime SDK for WPF API calls. 
  ESRI.ArcGIS.Client.ArcGISWebClient.DefaultCachePolicy = new System.Net.Cache.RequestCachePolicy(myRequestCacheLevel);
}
            
private void Button_Click_1(object sender, RoutedEventArgs e)
{
  // Create a new QueryTask. 
  ESRI.ArcGIS.Client.Tasks.QueryTask myQueryTask = null;
  myQueryTask = new ESRI.ArcGIS.Client.Tasks.QueryTask("http://sampleserver6.arcgisonline.com/arcgis/rest/services/SampleWorldCities/MapServer/0");
  
  // Execute the QueryTask. View the results of the web traffic in an applicaiton like Fiddler.
  myQueryTask.ExecuteAsync(new ESRI.ArcGIS.Client.Tasks.Query() { Where = "1=1" });
}

Public Sub New()
  
  InitializeComponent()
  
  ' Add the different System.Net.Cache.RequestCacheLevel to the ComboBox.
  RequestPolicyLevel.ItemsSource = New System.Net.Cache.RequestCacheLevel() {System.Net.Cache.RequestCacheLevel.BypassCache,
                                                                             System.Net.Cache.RequestCacheLevel.CacheIfAvailable,
                                                                             System.Net.Cache.RequestCacheLevel.CacheOnly,
                                                                             System.Net.Cache.RequestCacheLevel.Default,
                                                                             System.Net.Cache.RequestCacheLevel.NoCacheNoStore,
                                                                             System.Net.Cache.RequestCacheLevel.Reload,
                                                                             System.Net.Cache.RequestCacheLevel.Revalidate}
  
  ' Set the default item to appear in the ComboBox when the application loads.
  RequestPolicyLevel.SelectedItem = System.Net.Cache.RequestCacheLevel.Default
  
End Sub
            
Private Sub RequestPolicyLevel_SelectionChanged_1(ByVal sender As Object, ByVal e As SelectionChangedEventArgs)
  
  ' Get the System.Net.Cache.RequestCacheLevel from the selected ComboxBox selection.
  Dim myRequestCacheLevel As System.Net.Cache.RequestCacheLevel = CType((TryCast(sender, ComboBox)).SelectedItem, System.Net.Cache.RequestCacheLevel)
  
  ' Set the Shared/static ArcGISWebClient.DefaultCachePolicy Property. This will affect all ArcGIS Runtime SDK for WPF API calls. 
  ESRI.ArcGIS.Client.ArcGISWebClient.DefaultCachePolicy = New System.Net.Cache.RequestCachePolicy(myRequestCacheLevel)
  
End Sub
            
Private Sub Button_Click_1(ByVal sender As Object, ByVal e As RoutedEventArgs)
  
  ' Create a new QueryTask. 
  Dim myQueryTask As ESRI.ArcGIS.Client.Tasks.QueryTask
  myQueryTask = New ESRI.ArcGIS.Client.Tasks.QueryTask("http://sampleserver6.arcgisonline.com/arcgis/rest/services/SampleWorldCities/MapServer/0")
  
  ' Execute the QueryTask. View the results of the web traffic in an applicaiton like Fiddler.
  myQueryTask.ExecuteAsync(New ESRI.ArcGIS.Client.Tasks.Query() With {.Where = "1=1"})
  
End Sub