Public Property LayerDefinitions As ObservableCollection(Of LayerDefinition)

public ObservableCollection<LayerDefinition> LayerDefinitions {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">
         
         <!-- Set the LayerDefinition for the ArcGISDynamicMapServiceLayer. -->
         <!-- By default no LayerDefinition is set unless explicitly set on the server. -->
         <esri:ArcGISDynamicMapServiceLayer 
              Url="http://sampleserver3.arcgisonline.com/ArcGIS/rest/services/Earthquakes/Since_1970/MapServer" />
              <esri:ArcGISDynamicMapServiceLayer.LayerDefinitions>
                  
                  <!-- LayerID="0" is the Earthquakes1970 layer. The Definition only displays earth quakes that have a
                          Magnitude greater than 6. The field Magnitude is of type esriFieldTypeDouble. -->
                  <esri:LayerDefinition LayerID="0" Definition="Magnitude > 6" />
                  
                  <!-- LayerID="0" is the Earthquakes1970 layer. The Definition only displays earth quakes that have a
                          Magnitude greater than 3 and less than 6. The field Magnitude is of type esriFieldTypeDouble. -->
                  <!-- <esri:LayerDefinition LayerID="0" Definition="Magnitude > 3 AND Magnitude &lt; 6" /> -->
                  
                  <!-- Another example where the Name of the earth quake event is to contains the letters 'CHINA'.
                          Note: the Definition is case sensitive. The field Name is of type esriFieldTypeString. -->
                  <!-- <esri:LayerDefinition LayerID="0" Definition="Name LIKE 'CHINA'" /> -->
                  
                  <!-- Another example where the Name of the earth quake event is exactly matches the letters 'VENEZUELA'.
                          Note: the Definition is case sensitive. The field Name is of type esriFieldTypeString. -->
                  <!-- <esri:LayerDefinition LayerID="0" Definition="Name = 'VENEZUELA'" /> -->
                  
                  <!-- Another example where the earth quake events are displayed if they occured after January 15, 2000. 
                          The field Date_ is of type esriFieldTypeDate. -->
                  <!-- <esri:LayerDefinition LayerID="0" Definition="Date_ > DATE '1/15/2000'" />-->
                
              </esri:ArcGISDynamicMapServiceLayer.LayerDefinitions>
         </esri:ArcGISDynamicMapServiceLayer>
    </esri:Map>
    
    <!-- LayerDefinitions Property (Read) -->
    <TextBlock Height="23" Name="TextBlock_LayerDefinitions" 
        Text="{Binding ElementName=Map1, Path=Layers[0].LayerDefinitions[0].Definition}" />
</StackPanel>

private void ArcGISDynamicMapServiceLayer_Initialized(object sender, System.EventArgs e)
{
    
    // The myArcGISDynamicMapServiceLayer (an ArcGISDynamicServiceLayer object) and TextBlock_LayerDefinitions
    // (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];
            
    // LayerDefinition (Read/Write)
    
    // This is how to set (i.e. Write) a LayerDefinition.
    // --------------------------------------------------
    // Set the .LayerDefinition for the .LayerID = 0 (the Earthquakes1970 layer). By default no LayerDefinition 
    // is set unless explicitly set on the server.
    ESRI.ArcGIS.Client.LayerDefinition myDefinition = new ESRI.ArcGIS.Client.LayerDefinition();
    myDefinition.LayerID = 0;
    
    // The Definition only displays earth quakes that have a Magnitude greater than 6. 
    // The field Magnitude is of type esriFieldTypeDouble.
    myDefinition.Definition = "Magnitude > 6";
    
    // The Definition only displays earth quakes that have a Magnitude greater than 3 and less that 6. 
    // The field Magnitude is of type esriFieldTypeDouble.
    // myDefinition.Definition = "Magnitude > 3 AND Magnitude < 6";
             
    // Another example where the Name of the earth quake event is to contains the letters 'CHINA'.
    // Note: the Definition is case sensitive. The field Name is of type esriFieldTypeString.
    //myDefinition.Definition = "Name LIKE 'CHINA'";
    
    // Another example where the Name of the earth quake event is exactly matches the letters 'VENEZUELA'.
    // Note: the Definition is case sensitive. The field Name is of type esriFieldTypeString.
    //myDefinition.Definition = "Name = 'VENEZUELA'";
    
    // Another example where the earth quake events are displayed if they occured after January 15, 2000. 
    // The field Date_ is of type esriFieldTypeDate.
    //myDefinition.Definition = "Date_ > DATE '1/15/2000'";
    
    // Create an ObservableCollection and add the .Definition to it.
    System.Collections.ObjectModel.ObservableCollection<LayerDefinition> myObservableCollection2 = 
       new System.Collections.ObjectModel.ObservableCollection<LayerDefinition>();
    myObservableCollection2.Add(myDefinition);
    
    // Apply the custom LayerDefinition
    myArcGISDynamicMapServiceLayer.LayerDefinitions = myObservableCollection2;
    
    
    // This is how to get (i.e. Read) a LayerDefiniton.
    // The TextBlock_LayerDefinitions (a TextBlock object) was previously set in XAML or code-behind.
    // ----------------------------------------------------------------------------------------------
    // Get the existing LayerDefinitions collection.
    System.Collections.ObjectModel.ObservableCollection<LayerDefinition> myObservableCollection = 
        myArcGISDynamicMapServiceLayer.LayerDefinitions;
                
    if (myObservableCollection.Count > 0)
    {
        // Get the first LayerDefinition 
        ESRI.ArcGIS.Client.LayerDefinition myLayerDefinition = myObservableCollection[0];
        
        // Display some textual information about the LayerDefinition.
        TextBlock_LayerDefinitions.Text = "For Layer: " + myLayerDefinition.LayerID.ToString() + 
            ". The Defintion is: " + myLayerDefinition.Definition;
    }
    else
    {
        TextBlock_LayerDefinitions.Text = "[NO LayerDefinitions SET]";
    }
    
}

Private Sub ArcGISDynamicMapServiceLayer_Initialized(ByVal sender As System.Object, ByVal e As System.EventArgs)
    
    ' The myArcGISDynamicMapServiceLayer (an ArcGISDynamicServiceLayer object) and TextBlock_LayerDefinitions
    ' (a TextBlock object) were defined previously in the XAML or code-behind.
    
    ' Get the first layer in the LayerInfo collection. 
    Dim myArcGISDynamicMapServiceLayer As ArcGISDynamicMapServiceLayer = Map1.Layers.Item(0)
    
    ' LayerDefinition (Read/Write)
    
    ' This is how to set (i.e. Write) a LayerDefinition.
    ' --------------------------------------------------
    
    ' Set the .LayerDefinition for the .LayerID = 0 (the Earthquakes1970 layer). By default no LayerDefinition 
    ' is set unless explicitly set on the server.
    Dim myDefinition As New ESRI.ArcGIS.Client.LayerDefinition
    myDefinition.LayerID = 0
    
    ' The Definition only displays earth quakes that have a Magnitude greater than 6. 
    ' The field Magnitude is of type esriFieldTypeDouble.
    myDefinition.Definition = "Magnitude > 6"
    
    ' The Definition only displays earth quakes that have a Magnitude greater than 3 and less than 6. 
    ' The field Magnitude is of type esriFieldTypeDouble.
    'myDefinition.Definition = "Magnitude > 3 AND Magnitude < 6"
             
    ' Another example where the Name of the earth quake event is to contains the letters 'CHINA'.
    ' Note: the Definition is case sensitive. The field Name is of type esriFieldTypeString.
    'myDefinition.Definition = "Name LIKE 'CHINA'"
    
    ' Another example where the Name of the earth quake event is exactly matches the letters 'VENEZUELA'.
    ' Note: the Definition is case sensitive. The field Name is of type esriFieldTypeString.
    'myDefinition.Definition = "Name = 'VENEZUELA'"
    
    ' Another example where the earth quake events are displayed if they occured after January 15, 2000. 
    ' The field Date_ is of type esriFieldTypeDate.
    'myDefinition.Definition = "Date_ > DATE '1/15/2000'"
     
    ' Create an ObservableCollection and add the .Definition to it.
    Dim myObservableCollection2 As New System.Collections.ObjectModel.ObservableCollection(Of LayerDefinition)
    myObservableCollection2.Add(myDefinition)
    
    ' Apply the custom LayerDefinition
    myArcGISDynamicMapServiceLayer.LayerDefinitions = myObservableCollection2
    
    
    ' This is how to get (i.e. Read) a LayerDefiniton.
    ' The TextBlock_LayerDefinitions (a TextBlock object) was previously set in XAML or code-behind.
    ' ----------------------------------------------------------------------------------------------
    ' Get the existing LayerDefinitions collection.
    Dim myObservableCollection As System.Collections.ObjectModel.ObservableCollection(Of LayerDefinition) = _
        myArcGISDynamicMapServiceLayer.LayerDefinitions
    
    If myObservableCollection.Count > 0 Then
    
        ' Get the first LayerDefinition 
        Dim myLayerDefinition As LayerDefinition = myObservableCollection.Item(0)
        
        ' Display some textual information about the LayerDefinition.
        TextBlock_LayerDefinitions.Text = "For Layer: " + myLayerDefinition.LayerID.ToString + _
            ". The Defintion is: " + myLayerDefinition.Definition
    Else
        TextBlock_LayerDefinitions.Text = "[NO LayerDefinitions SET]"
    End If
    
End Sub