Public Sub SetZIndex( _
   ByVal value As Integer _
) 

public void SetZIndex( 
   int value
)

<Grid x:Name="LayoutRoot">
  
  <!-- Add a Map control with an ArcGISTiledMapServiceLayer. -->
  <esri:Map Background="White" HorizontalAlignment="Left" Margin="12,111,0,0" Name="Map1" 
            VerticalAlignment="Top" Height="318" Width="483" >
    <esri:ArcGISTiledMapServiceLayer ID="PhysicalTiledLayer" 
             Url="http://services.arcgisonline.com/ArcGIS/rest/services/World_Street_Map/MapServer"/>
  </esri:Map>
  
  <!-- Provide the instructions on how to use the sample code. -->
  <TextBlock Height="64" HorizontalAlignment="Left" Name="TextBlock1" VerticalAlignment="Top" 
           Width="512" TextWrapping="Wrap" Margin="12,12,0,0" 
           Text="Click the button to draw some Graphics in the Map. The Graphics will have 
                 Z-Index values assigned. Each Graphic will be rendered using a TextSymbol
                 that displays its Z-Index value." />
    
  <!-- 
  Add a Button to perform the work. Note: the Click Event handler is wired-up to use 
  code-behind. 
  -->
  <Button Content="Display the Graphics Z-Index values via TextSymbols." Height="23" 
          HorizontalAlignment="Left" Margin="93,82,0,0" 
          Name="Button1"  VerticalAlignment="Top" Width="319" Click="Button1_Click"/>
  
</Grid>

private void Button1_Click(object sender, System.Windows.RoutedEventArgs e)
{
  // This is the main function will add a new GraphicsLayer to the Map. The GraphicsLayer will contain 
  // Graphics based upon MapPoint geometries. As part of the example code, the Graphics will be assigned
  // Z-Index values. The Z-Index values will be displayed as TextSymbols for ease of viewing.
  
  // Create a new instance of the GraphicsLayer object 
  ESRI.ArcGIS.Client.GraphicsLayer myGraphicsLayer = new ESRI.ArcGIS.Client.GraphicsLayer();
  
  // Add a few graphics to the GraphicsLayer
  myGraphicsLayer.Graphics.Add(MakeGraphic(-7356594.25, 4752385.95, 102100));
  myGraphicsLayer.Graphics.Add(MakeGraphic(5468910.57, 1875915.58, 102100));
  myGraphicsLayer.Graphics.Add(MakeGraphic(-1558708.66, -326382.05, 102100));
  myGraphicsLayer.Graphics.Add(MakeGraphic(8614958.43, -4191639.11, 102100));
  
  // Assign some Z-Index values to the Graphics.
  AssignZIndexValues(myGraphicsLayer);
  
  // Assign a TextSymbol to the Graphics that use the Z-Index values.
  AssignTextSymbol(myGraphicsLayer);
  
  // Add the GraphicsLayer to the Layers collection of the Map (this will automatically cause a refresh 
  // of the Map). 
  Map1.Layers.Add(myGraphicsLayer);
}
            
public object MakeGraphic(double X, double Y, int SR)
{
  // This function constructs a new Graphic. Note: the symbology has not been defined at this point.
  
  // Create a SpatialReference for the Graphic.
  ESRI.ArcGIS.Client.Geometry.SpatialReference aSpatialReference = new ESRI.ArcGIS.Client.Geometry.SpatialReference(SR);
  
  // Create a MapPoint object and set its SpatialReference and coordinate (X,Y) information. 
  ESRI.ArcGIS.Client.Geometry.MapPoint aMapPoint = new ESRI.ArcGIS.Client.Geometry.MapPoint(X, Y, aSpatialReference);
  
  // Create a new instance of one Graphic and assigen its Geometry.
  ESRI.ArcGIS.Client.Graphic aGraphic = new ESRI.ArcGIS.Client.Graphic();
  aGraphic.Geometry = (ESRI.ArcGIS.Client.Geometry.Geometry)aMapPoint;
  
  // Return the created Graphic.
  return aGraphic;
}
  
public void AssignZIndexValues(ESRI.ArcGIS.Client.GraphicsLayer theGraphicsLayer)
{
  // This function set the Z Index value in the same order as the Graphics in the GraphicsLayer. 
  
  // Get the GraphicCollection from the GraphicsLayer.
  ESRI.ArcGIS.Client.GraphicCollection theGraphicCollection = theGraphicsLayer.Graphics;
  
  // Create a counter.
  int myindex = 0;
  
  // Loop through each Graphic in the GraphicCollection
  foreach (ESRI.ArcGIS.Client.Graphic aGraphic in theGraphicCollection)
  {
    // Set the Z Index value by the counter.
    aGraphic.SetZIndex(myindex);
    
    // Incriment the counter.
    myindex = myindex + 1;
  }
}
            
public void AssignTextSymbol(ESRI.ArcGIS.Client.GraphicsLayer theGraphicsLayer)
{
  // This function assigns a TextSymbol to the Graphics in the GraphicsLayer. The TextSymbol.Text
  // Property uses the existing Graphics Z-Index value.
  
  // Get the GraphicCollection from the GraphicsLayer.
  ESRI.ArcGIS.Client.GraphicCollection theGraphicCollection = theGraphicsLayer.Graphics;
  
  // Loop through each Graphic in the GraphicCollection
  foreach (ESRI.ArcGIS.Client.Graphic aGraphic in theGraphicCollection)
  {
    // Create a new TextSymbol and define its look. The strings used to define the FontFamily can be
    // found in the following MSDN documentation:
    // http://msdn.microsoft.com/en-us/library/cc189010(v=VS.95).aspx
    ESRI.ArcGIS.Client.Symbols.TextSymbol aTextSymbol = new ESRI.ArcGIS.Client.Symbols.TextSymbol();
    aTextSymbol.FontFamily = new FontFamily("Arial");
    aTextSymbol.FontSize = 20;
    aTextSymbol.Foreground = new System.Windows.Media.SolidColorBrush(Colors.Red);
    
    // Set the TextSymbol.Text Property to the Z-Index value that was assigend previosuly.
    aTextSymbol.Text = aGraphic.GetZIndex;
    
    // Assign the TextSymbol as the Graphic.Symbol as this was not previously done.
    aGraphic.Symbol = (ESRI.ArcGIS.Client.Symbols.Symbol)aTextSymbol;
  }
}

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.Windows.RoutedEventArgs)
  
  ' This is the main function will add a new GraphicsLayer to the Map. The GraphicsLayer will contain 
  ' Graphics based upon MapPoint geometries. As part of the example code, the Graphics will be assigned
  ' Z-Index values. The Z-Index values will be displayed as TextSymbols for ease of viewing.
  
  ' Create a new instance of the GraphicsLayer object 
  Dim myGraphicsLayer As New ESRI.ArcGIS.Client.GraphicsLayer
  
  ' Add a few graphics to the GraphicsLayer
  myGraphicsLayer.Graphics.Add(MakeGraphic(-7356594.25, 4752385.95, 102100))
  myGraphicsLayer.Graphics.Add(MakeGraphic(5468910.57, 1875915.58, 102100))
  myGraphicsLayer.Graphics.Add(MakeGraphic(-1558708.66, -326382.05, 102100))
  myGraphicsLayer.Graphics.Add(MakeGraphic(8614958.43, -4191639.11, 102100))
  
  ' Assign some Z-Index values to the Graphics.
  AssignZIndexValues(myGraphicsLayer)
  
  ' Assign a TextSymbol to the Graphics that use the Z-Index values.
  AssignTextSymbol(myGraphicsLayer)
  
  ' Add the GraphicsLayer to the Layers collection of the Map (this will automatically cause a refresh of the Map). 
  Map1.Layers.Add(myGraphicsLayer)
  
End Sub
  
Public Function MakeGraphic(ByVal X As Double, ByVal Y As Double, ByVal SR As Integer)
  
  ' This function constructs a new Graphic. Note: the symbology has not been defined at this point.
  
  ' Create a SpatialReference for the Graphic.
  Dim aSpatialReference As New ESRI.ArcGIS.Client.Geometry.SpatialReference(SR)
  
  ' Create a MapPoint object and set its SpatialReference and coordinate (X,Y) information. 
  Dim aMapPoint As New ESRI.ArcGIS.Client.Geometry.MapPoint(X, Y, aSpatialReference)
  
  ' Create a new instance of one Graphic and assigen its Geometry.
  Dim aGraphic As New ESRI.ArcGIS.Client.Graphic
  aGraphic.Geometry = CType(aMapPoint, ESRI.ArcGIS.Client.Geometry.Geometry)
  
  ' Return the created Graphic.
  Return aGraphic
  
End Function
  
Public Sub AssignZIndexValues(ByVal theGraphicsLayer As ESRI.ArcGIS.Client.GraphicsLayer)
  
  ' This function set the Z Index value in the same order as the Graphics in the GraphicsLayer. 
  
  ' Get the GraphicCollection from the GraphicsLayer.
  Dim theGraphicCollection As ESRI.ArcGIS.Client.GraphicCollection = theGraphicsLayer.Graphics
  
  ' Create a counter.
  Dim myindex As Integer = 0
  
  ' Loop through each Graphic in the GraphicCollection
  For Each aGraphic As ESRI.ArcGIS.Client.Graphic In theGraphicCollection
    
    ' Set the Z Index value by the counter.
    aGraphic.SetZIndex(myindex)
    
    ' Incriment the counter.
    myindex = myindex + 1
    
  Next
  
End Sub
  
Public Sub AssignTextSymbol(ByVal theGraphicsLayer As ESRI.ArcGIS.Client.GraphicsLayer)
  
  ' This function assigns a TextSymbol to the Graphics in the GraphicsLayer. The TextSymbol.Text
  ' Property uses the existing Graphics Z-Index value.
  
  ' Get the GraphicCollection from the GraphicsLayer.
  Dim theGraphicCollection As ESRI.ArcGIS.Client.GraphicCollection = theGraphicsLayer.Graphics
  
  ' Loop through each Graphic in the GraphicCollection
  For Each aGraphic As ESRI.ArcGIS.Client.Graphic In theGraphicCollection
    
    ' Create a new TextSymbol and define its look. The strings used to define the FontFamily can be
    ' found in the following MSDN documentation:
    ' http://msdn.microsoft.com/en-us/library/cc189010(v=VS.95).aspx
    Dim aTextSymbol As New ESRI.ArcGIS.Client.Symbols.TextSymbol
    aTextSymbol.FontFamily = New FontFamily("Arial")
    aTextSymbol.FontSize = 20
    aTextSymbol.Foreground = New System.Windows.Media.SolidColorBrush(Colors.Red)
    
    ' Set the TextSymbol.Text Property to the Z-Index value that was assigend previosuly.
    aTextSymbol.Text = aGraphic.GetZIndex
    
    ' Assign the TextSymbol as the Graphic.Symbol as this was not previously done.
    aGraphic.Symbol = CType(aTextSymbol, ESRI.ArcGIS.Client.Symbols.Symbol)
    
  Next
  
End Sub