Public ReadOnly Property CopyrightText As String

public string CopyrightText {get;}

<Grid x:Name="LayoutRoot">
  
  <!-- Add a Map Control. Set its Initial Extent to Iowa. -->
  <esri:Map Background="White" HorizontalAlignment="Left" Margin="0,180,0,0" Name="Map1" 
          VerticalAlignment="Top" Height="300" Width="400" Extent="-96.89,39.47,-89.91,44.70">
  
    <!-- Define an ArcGISDynamicMapServiceLayer. -->
    <esri:ArcGISDynamicMapServiceLayer 
          Url="http://sampleserver1.arcgisonline.com:80/arcgis/rest/services/Specialty/ESRI_StateCityHighway_USA/MapServer"
          Initialized="ArcGISDynamicMapServiceLayer_Initialized"/>
    
  </esri:Map>
  
  <!-- CopyrightText (Read Only). -->
  <sdk:Label Height="24" HorizontalAlignment="Left" Margin="0,88,0,0" Name="Label_CopyrightText" 
             VerticalAlignment="Top" Width="120" Content="CopyrightText:"/>
  <TextBox Height="69" HorizontalAlignment="Left" Margin="0,105,0,0" Name="TextBox_CopyrightText" 
           VerticalAlignment="Top" Width="400" TextWrapping="Wrap" />
  
  <!-- 
  As an alternative you could bind the ArcGISDynamicMapServiceLayer.CopyrightText directly to the
  TextBox.Text Property and not need to put any code in the code-behind for the 
  ArcGISDynamicMapServiceLayer.Initialized Event.
  -->
  <!--<TextBox Height="69" HorizontalAlignment="Left" Margin="0,105,0,0" Name="TextBox_CopyrightText" TextWrapping="Wrap"
           VerticalAlignment="Top" Width="400" Text="{Binding ElementName=Map1, Path=Layers[0].CopyrightText}"/>-->
  
  <!-- Provide the instructions on how to use the sample code. -->
  <TextBlock Height="52" HorizontalAlignment="Left" Name="TextBlock1" VerticalAlignment="Top" Width="400" 
       TextWrapping="Wrap" Text="When the ArcGISDynamicMapServiceLayer Initializes the CopyrightText
       will be automatically populated in the TextBlock." />
      
</Grid>

private void ArcGISDynamicMapServiceLayer_Initialized(object sender, System.EventArgs e)
{
  // Get the first layer in the Map. 
  ESRI.ArcGIS.Client.ArcGISDynamicMapServiceLayer myArcGISDynamicMapServiceLayer = null;
  myArcGISDynamicMapServiceLayer = (ESRI.ArcGIS.Client.ArcGISDynamicMapServiceLayer)(Map1.Layers[0]);
  
  // CopyrightText (Read Only).
  // NOTE: The CopyrightText information is set in the Credits section on the General tab of the Data Frame 
  // Properties dialog in ArcMap.
  TextBox_CopyrightText.Text = myArcGISDynamicMapServiceLayer.CopyrightText;
}

Private Sub ArcGISDynamicMapServiceLayer_Initialized(ByVal sender As System.Object, ByVal e As System.EventArgs)
  
  ' Get the first layer in the Map. 
  Dim myArcGISDynamicMapServiceLayer As ESRI.ArcGIS.Client.ArcGISDynamicMapServiceLayer
  myArcGISDynamicMapServiceLayer = CType(Map1.Layers.Item(0), ESRI.ArcGIS.Client.ArcGISDynamicMapServiceLayer)
  
  ' CopyrightText (Read Only).
  ' NOTE: The CopyrightText information is set in the Credits section on the General tab of the Data Frame 
  ' Properties dialog in ArcMap.
  TextBox_CopyrightText.Text = myArcGISDynamicMapServiceLayer.CopyrightText
  
End Sub