Public Property VisibleLayers As Integer()

public int[] VisibleLayers {get; set;}

private void ArcGISDynamicMapServiceLayer_Initialized(object sender, System.EventArgs e)
{
  // The myArcGISDynamicMapServiceLayer (an ArcGISDynamicServiceLayer object) and TextBlock_VisibleLayers 
  // (a TextBlock object) were defined previously in the XAML or code-behind.
  
  // Get the first layer in the LayerInfo collection. 
  ArcGISDynamicMapServiceLayer myArcGISDynamicMapServiceLayer = (ArcGISDynamicMapServiceLayer)Map1.Layers[0];
  
  // VisibleLayers (Read/Write)
  // ========================== 
  
  // In this example there are three sub-layers (0, 1, 2) that are turned on by default for the 
  // myArcGISDynamicMapServiceLayer. 
  
  // Uncomment the next two lines of code to set only the 2nd and 3rd sub-layers to be visible.
  //int[] myVisibleLayers2 = { 1, 2 }; 
  //myArcGISDynamicMapServiceLayer.VisibleLayers = myVisibleLayers2;
  
  // Display which sub-layers (via their index number) are visible in a TextBlock.
  int[] myVisibleLayers = myArcGISDynamicMapServiceLayer.VisibleLayers;
  if (myVisibleLayers != null)
  {
    string myVisibleLayersText = "Number VisibleLayers: " + myVisibleLayers.Length.ToString();
    string myVisibleLayersText2 = "";
    int I2 = 0;
    for (I2 = 0; I2 < myVisibleLayers.Length; I2++)
    {
      myVisibleLayersText2 = myVisibleLayersText2 + " " + myVisibleLayers[I2].ToString();
    }
    TextBlock_VisibleLayers.Text = myVisibleLayersText + ". VisibleLayers ID's: " + myVisibleLayersText2;
  }
  else
  {
    TextBlock_VisibleLayers.Text = "[VisibleLayers not set - Meaning all layers are visible.]";
  }
  
}

Private Sub ArcGISDynamicMapServiceLayer_Initialized(ByVal sender As System.Object, ByVal e As System.EventArgs)
            
  ' The myArcGISDynamicMapServiceLayer (an ArcGISDynamicServiceLayer object) and TextBlock_VisibleLayers 
  ' (a TextBlock object) were defined previously in the XAML or code-behind.
  
  ' Get the first layer in the LayerInfo collection. 
  Dim myArcGISDynamicMapServiceLayer As ESRI.ArcGIS.Client.ArcGISDynamicMapServiceLayer = Map1.Layers.Item(0)
  
  ' VisibleLayers (Read/Write)
  ' ==========================
            
  ' In this example there are three sub-layers (0, 1, 2) that are turned on by default for the 
  ' myArcGISDynamicMapServiceLayer. 
            
  ' Uncomment the next two lines of code to set only the 2nd and 3rd sub-layers to be visible.
  'Dim myVisibleLayers2() As Integer = {1, 2}
  'myArcGISDynamicMapServiceLayer.VisibleLayers = myVisibleLayers2
            
  ' Display which sub-layers (via their index number) are visible in a TextBlock.
  Dim myVisibleLayers() As Integer = myArcGISDynamicMapServiceLayer.VisibleLayers
  If myVisibleLayers IsNot Nothing Then
    Dim myVisibleLayersText As String = "Number VisibleLayers: " + myVisibleLayers.Length.ToString
    Dim myVisibleLayersText2 As String = ""
    Dim I2 As Integer
    For I2 = 0 To myVisibleLayers.Length - 1
      myVisibleLayersText2 = myVisibleLayersText2 + " " + myVisibleLayers(I2).ToString
    Next
    TextBlock_VisibleLayers.Text = myVisibleLayersText + ". VisibleLayers ID's: " + myVisibleLayersText2
  Else
    TextBlock_VisibleLayers.Text = "[VisibleLayers not set - Meaning all layers are visible.]"
  End If
  
End Sub