Public Property Url As String

public string Url {get; set;}

<StackPanel Name="StackPanel1" Height="400" Width="400" Margin="0,0,0,0" HorizontalAlignment="Left" VerticalAlignment="Top" >
    <esri:Map Background="White" Name="Map1" Height="200" Width="400">
    
         <!-- Define an ArcGISImageServiceLayer. -->
         <esri:ArcGISImageServiceLayer 
              Url="http://sampleserver3.arcgisonline.com/ArcGIS/rest/services/Portland/CascadeLandsat/ImageServer" />
              
    </esri:Map>
    
    <!-- Url Property (Read/Write) -->
    <TextBlock Height="23" Name="TextBlock_Url" Text="{Binding ElementName=Map1, Path=Layers[0].Url}" />
</StackPanel>

private void MainPage_Loaded(object sender, System.Windows.RoutedEventArgs e)
{
     
  // Create an ArcGISImageServiceLayer. The Map1 object (a Map class) was previously defined in XAML.
  ESRI.ArcGIS.Client.ArcGISImageServiceLayer myArcGISImageServiceLayer = new ESRI.ArcGIS.Client.ArcGISImageServiceLayer();
 
     // Set the URL.
  myArcGISImageServiceLayer.Url = "http://sampleserver3.arcgisonline.com/ArcGIS/rest/services/Portland/CascadeLandsat/ImageServer";
  
     // Wire-up the event handler.
  myArcGISImageServiceLayer.Initialized += new EventHandler<EventArgs>(ArcGISImageServiceLayer_Initialized);
     
     // Add the ArcGISImageServiceLayer to the Map control.
  Map1.Layers.Add(myArcGISImageServiceLayer);
  
}
             	
private void ArcGISImageServiceLayer_Initialized(object sender, System.EventArgs e)
{
             	
  // The TextBlock_Url (a TextBlock object) was defined previously in the XAML.
            
  //Access a specific layer:
  ESRI.ArcGIS.Client.ArcGISImageServiceLayer myArcGISImageServiceLayer = (ESRI.ArcGIS.Client.ArcGISImageServiceLayer)Map1.Layers[0];
             	
  //Url (Read/Write)
  string myUrl = myArcGISImageServiceLayer.Url;
  if (myUrl != null)
  {
    TextBlock_Url.Text = "Url: " + myUrl;
  }
  else
  {
    TextBlock_Url.Text = "[NO Url SET]";
  }
  
}

Private Sub MainPage_Loaded(ByVal sender As Object, ByVal e As System.Windows.RoutedEventArgs) Handles Me.Loaded
             	
  ' Create an ArcGISImageServiceLayer. The Map1 object (a Map class) was previously defined in XAML.
  Dim myArcGISImageServiceLayer As New ESRI.ArcGIS.Client.ArcGISImageServiceLayer
 
     ' Set the URL.
  myArcGISImageServiceLayer.Url = "http://sampleserver3.arcgisonline.com/ArcGIS/rest/services/Portland/CascadeLandsat/ImageServer"
  
     ' Wire-up the event handler.
  AddHandler myArcGISImageServiceLayer.Initialized, AddressOf ArcGISImageServiceLayer_Intialized
     
     ' Add the ArcGISImageServiceLayer to the Map control.
  Map1.Layers.Add(myArcGISImageServiceLayer)
  
End Sub
             	
Private Sub ArcGISImageServiceLayer_Initialized(ByVal sender As System.Object, ByVal e As System.EventArgs)
             	
  ' The TextBlock_Url (a TextBlock object) was defined previously in the XAML.
     
  'Access a specific layer:
  Dim myArcGISImageServiceLayer As ESRI.ArcGIS.Client.ArcGISImageServiceLayer = Map1.Layers.Item(0)
             	
  'Url (Read/Write)
  Dim myUrl As String = myArcGISImageServiceLayer.Url
  If myUrl IsNot Nothing Then
    TextBlock_Url.Text = "Url: " + myUrl
  Else
    TextBlock_Url.Text = "[NO Url SET]"
  End If
             	
End Sub