ArcGIS API for Silverlight - Library Reference
Layers Property
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ESRI.ArcGIS.Client Namespace > Map Class : Layers Property

Gets or sets the LayerCollection of Layer objects in the Map Control.

Syntax

Visual Basic (Declaration) 
Public Property Layers As LayerCollection
C# 
public LayerCollection Layers {get; set;}

Remarks

The Layers Property always returns a LayerCollection object; it is never Nothing/null. If no layers are added to the Map the LayerCollection.Count = 0.

Do not confuse the results of a Map.Layers Property (which returns a LayerCollection object) with the ArcGISTiledMapServiceLayer.Layers and ArcGISDynamicMapServicelayer.Layers Properties (which return a LayerInfo() object). The LayerInfo() is an array of LayerInfo objects and is often referred to in the documentation as a ‘sub-layers’.

Note: Accessing a specific Layer via XAML can be done with or without drilling through the <esri:Map.Layers> tag. The following two abbreviated XAML code fragments are equivalent: 

            <Grid>
              <esri: Map>
                <esri:Map.Layers>
                  <esri:ArcGISDynamicMapServiceLayer/>
                </esri:Map.Layers>
              </esri:Map>
            </Grid>
            


            <Grid>
              <esri: Map>
                <esri:ArcGISDynamicMapServiceLayer/>
              </esri:Map>
            </Grid>

Accessing an individual Layer in the LayerCollection in code-behind can be done either by its index number, ID (string name), or via iterating over the LayerCollection. In XAML it is not possible to iterate over a collection using a For/Each loop so accessing a Layer in the LayerCollection is done using either its index number or ID (string name). When using XAML is may be necessary to escape special characters when accessing a Layer via it’s ID (string name); for example a ‘space’ in the name should be escaped with &#32;. The screen shot and code example in this document demonstrates the alternatives for accessing Layers in a LayerCollection.

Accessing Layers and their information using different techniques from the LayerCollection.

Example

XAMLCopy Code
<!-- 
Add the following types of Layers to the Map Control: ArcGISTiledMapsServiceLayer, FeatureLayer,
and ArcGISDynamicServiceLayer. Zoom to Southern California.
-->
<esri:Map Name="Map1" Background="White" Margin="12,12,0,0" Height="331" Width="883" Extent="-121,30,-113,38">
  <esri:Map.Layers>
    <esri:ArcGISTiledMapServiceLayer 
          Url="http://services.arcgisonline.com/ArcGIS/rest/services/ESRI_StreetMap_World_2D/MapServer"/>
    <esri:FeatureLayer 
          Url="http://serverapps.esri.com/ArcGIS/rest/services/California/MapServer/8"/>
    <esri:ArcGISDynamicMapServiceLayer 
          ID="California Points" Url="http://serverapps.esri.com/ArcGIS/rest/services/California/MapServer"/>
  </esri:Map.Layers>
</esri:Map>
  
<!--
Obtain the Layers via their index number and ID. Display various information about each layer in TextBlocks.
-->
<TextBlock Name="TB_NumberOfLayers" Text="{Binding ElementName=Map1, Path=Layers.Count}" 
           Height="23" Width="56" Margin="12,349,839,68" />
<TextBlock Name="TB_FirstLayer_Type" Text="{Binding ElementName=Map1, Path=Layers[0]}" 
           Height="23" Width="281" Margin="12,366,614,52"/>
<TextBlock Name="TB_SecondLayer_Visible" Text="{Binding ElementName=Map1, Path=Layers[1].Visible}" 
           Height="23" Width="31" Margin="12,385,864,32" />
<TextBlock Name="TB_ThirdLayer_Opacity" Text="{Binding ElementName=Map1, Path=Layers[California&#32;Points].Opacity}" 
           Height="23" Width="31" Margin="12,405,864,12"/>
C#Copy Code
public void AddLayers()
{
  // Clear out any existing layers.
  Map1.Layers.Clear();
  
  // Add an ArcGISTiledMapsServiceLayer to the Map.
  ESRI.ArcGIS.Client.ArcGISTiledMapServiceLayer myArcGISTiledMapServiceLayer = new ESRI.ArcGIS.Client.ArcGISTiledMapServiceLayer();
  myArcGISTiledMapServiceLayer.Url = "http://services.arcgisonline.com/ArcGIS/rest/services/ESRI_StreetMap_World_2D/MapServer";
  Map1.Layers.Add(myArcGISTiledMapServiceLayer);
  
  // Add a FeatureLayer to the Map.
  ESRI.ArcGIS.Client.FeatureLayer myFeatureLayer = new ESRI.ArcGIS.Client.FeatureLayer();
  myFeatureLayer.Url = "http://serverapps.esri.com/ArcGIS/rest/services/California/MapServer/8";
  Map1.Layers.Add(myFeatureLayer);
  
  // Add an ArcGISDynamicServiceLayer to the Map.
  ESRI.ArcGIS.Client.ArcGISDynamicMapServiceLayer myArcGISDynamicMapServiceLayer = new ESRI.ArcGIS.Client.ArcGISDynamicMapServiceLayer();
  myArcGISDynamicMapServiceLayer.Url = "http://serverapps.esri.com/ArcGIS/rest/services/California/MapServer";
  myArcGISDynamicMapServiceLayer.ID = "California Points";
  Map1.Layers.Add(myArcGISDynamicMapServiceLayer);
  
  // Zoom into the Southern California.
  Map1.Extent = new ESRI.ArcGIS.Client.Geometry.Envelope(-121, 30, -113, 38);
}
  
public void GetLayerInfomation()
{
  // Obtain the first Layer in the LayerCollection via it's index number.
  ESRI.ArcGIS.Client.Layer firstLayer = Map1.Layers[0];
  
  // Obtain the second Layer in the LayerCollection via iterating over the collection.
  ESRI.ArcGIS.Client.Layer secondLayer = null;
  foreach (object x in Map1.Layers)
  {
    if (x is ESRI.ArcGIS.Client.FeatureLayer)
    {
      secondLayer = (ESRI.ArcGIS.Client.Layer)x;
    }
  }
  
  // Obtain the third Layer in the LayerCollection via it's ID (string name).
  ESRI.ArcGIS.Client.Layer thirdLayer = Map1.Layers["California Points"];
  
  // Display various information about each layer in a MessageBox.
  System.Text.StringBuilder sb_LayerInfo = new System.Text.StringBuilder();
  sb_LayerInfo.Append("The number of layers in the Map: " + Map1.Layers.Count.ToString() + System.Environment.NewLine + System.Environment.NewLine);
  sb_LayerInfo.Append("The 'firstLayer' is of Type: " + firstLayer.GetType().ToString() + System.Environment.NewLine);
  sb_LayerInfo.Append("The 'secondLayer' is Visible: " + secondLayer.Visible.ToString() + System.Environment.NewLine);
  sb_LayerInfo.Append("The 'thirdLayer' has an Opacity of: " + thirdLayer.Opacity.ToString());
  MessageBox.Show(sb_LayerInfo.ToString());
}
VB.NETCopy Code
Public Sub AddLayers()
            
  ' Clear out any existing layers.
  Map1.Layers.Clear()
  
  ' Add an ArcGISTiledMapsServiceLayer to the Map.
  Dim myArcGISTiledMapServiceLayer As New ESRI.ArcGIS.Client.ArcGISTiledMapServiceLayer
  myArcGISTiledMapServiceLayer.Url = "http://services.arcgisonline.com/ArcGIS/rest/services/ESRI_StreetMap_World_2D/MapServer"
  Map1.Layers.Add(myArcGISTiledMapServiceLayer)
  
  ' Add a FeatureLayer to the Map.
  Dim myFeatureLayer As New ESRI.ArcGIS.Client.FeatureLayer
  myFeatureLayer.Url = "http://serverapps.esri.com/ArcGIS/rest/services/California/MapServer/8"
  Map1.Layers.Add(myFeatureLayer)
  
  ' Add an ArcGISDynamicServiceLayer to the Map.
  Dim myArcGISDynamicMapServiceLayer As New ESRI.ArcGIS.Client.ArcGISDynamicMapServiceLayer
  myArcGISDynamicMapServiceLayer.Url = "http://serverapps.esri.com/ArcGIS/rest/services/California/MapServer"
  myArcGISDynamicMapServiceLayer.ID = "California Points"
  Map1.Layers.Add(myArcGISDynamicMapServiceLayer)
  
  ' Zoom into the Southern California.
  Map1.Extent = New ESRI.ArcGIS.Client.Geometry.Envelope(-121, 30, -113, 38)
  
End Sub
  
Public Sub GetLayerInfomation()
  
  ' Obtain the first Layer in the LayerCollection via it's index number.
  Dim firstLayer As ESRI.ArcGIS.Client.Layer = Map1.Layers(0)
  
  ' Obtain the second Layer in the LayerCollection via iterating over the collection.
  Dim secondLayer As ESRI.ArcGIS.Client.Layer = Nothing
  Dim x As Object
  For Each x In Map1.Layers
    If TypeOf x Is ESRI.ArcGIS.Client.FeatureLayer Then
        secondLayer = x
    End If
  Next
  
  ' Obtain the third Layer in the LayerCollection via it's ID (string name).
  Dim thirdLayer As ESRI.ArcGIS.Client.Layer = Map1.Layers("California Points")
  
  ' Display various information about each layer in a MessageBox.
  Dim sb_LayerInfo As New System.Text.StringBuilder
  sb_LayerInfo.Append("The number of layers in the Map: " + Map1.Layers.Count.ToString + vbCrLf + vbCrLf)
  sb_LayerInfo.Append("The 'firstLayer' is of Type: " + firstLayer.GetType.ToString + vbCrLf)
  sb_LayerInfo.Append("The 'secondLayer' is Visible: " + secondLayer.Visible.ToString + vbCrLf)
  sb_LayerInfo.Append("The 'thirdLayer' has an Opacity of: " + thirdLayer.Opacity.ToString)
  MessageBox.Show(sb_LayerInfo.ToString)
  
End Sub

Requirements

Target Platforms: Windows XP Professional, Windows Server 2003 family, Windows Vista, Windows Server 2008 family, Windows 7

See Also

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