Public Property Extent As Envelope

public Envelope Extent {get; set;}

<Grid x:Name="LayoutRoot" Background="White">
  
  <!--
  Add an ArcGISTiledMapsServiceLayer to the Map.
  Set the initial Extent of the Map (Continental US).
  -->
  <esri:Map Name="Map1" Height="300" Width="300" HorizontalAlignment="Left" VerticalAlignment="Top"
        Extent="-130,5,-70,65">
    <esri:ArcGISTiledMapServiceLayer Url="http://services.arcgisonline.com/ArcGIS/rest/services/ESRI_StreetMap_World_2D/MapServer"/>
  </esri:Map>
  
  <!--
  Display the Map's Extent Properties in TextBlocks.
  -->
  <TextBlock Name="TextBlock_XMin" Height="23" HorizontalAlignment="Left" Margin="306,42,0,0"  
             Text="{Binding ElementName=Map1, Path=Extent.XMin}" VerticalAlignment="Top" />
  <TextBlock Name="TextBlock_YMin" Height="23" HorizontalAlignment="Left" Margin="306,63,0,0"  
             Text="{Binding ElementName=Map1, Path=Extent.YMin}" VerticalAlignment="Top" />
  <TextBlock Name="TextBlock_XMax" Height="23" HorizontalAlignment="Left" Margin="306,83,0,0"  
             Text="{Binding ElementName=Map1, Path=Extent.XMax}" VerticalAlignment="Top" />
  <TextBlock Name="TextBlock_YMax" Height="23" HorizontalAlignment="Left" Margin="306,101,0,0"  
             Text="{Binding ElementName=Map1, Path=Extent.YMax}" VerticalAlignment="Top" />
 </Grid>

// A Map Control (named myMap) was previously added in to the project either in XAML or code-behind.
            
public void SetExtent(ESRI.ArcGIS.Client.Map myMap)
{
  
  // Clear out any existing layers.
  myMap.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";
  myMap.Layers.Add(myArcGISTiledMapServiceLayer);
  
  // Set the initial Extent of the Map (Continental US).
  ESRI.ArcGIS.Client.Geometry.Envelope myEnvelope = new ESRI.ArcGIS.Client.Geometry.Envelope();
  myEnvelope.XMin = -130;
  myEnvelope.YMin = 5;
  myEnvelope.XMax = -70;
  myEnvelope.YMax = 65;
  myMap.Extent = myEnvelope;
  
}
  
public void GetExtent(ESRI.ArcGIS.Client.Map mymap)
{
  
  // Extent (Read/Write)
  // Returns Nothing/null if no layers added to Map.
  ESRI.ArcGIS.Client.Geometry.Envelope myEnvelope = new ESRI.ArcGIS.Client.Geometry.Envelope();
  myEnvelope = mymap.Extent;
  
  // Return the Map.Extent in a MessageBox
  string myString = null;
  if (myEnvelope != null)
  {
      myString = "The Map.Extent is:" + System.Environment.NewLine + "XMin: " + mymap.Extent.XMin.ToString() + System.Environment.NewLine + "YMin: " + mymap.Extent.YMin.ToString() + System.Environment.NewLine + "XMax: " + mymap.Extent.XMax.ToString() + System.Environment.NewLine + "YMax:" + mymap.Extent.YMax.ToString();
  }
  else
  {
      myString = "No Map.Extent set.";
  }
  System.Windows.MessageBox.Show(myString);
}

' A Map Control (named myMap) was previously added in to the project either in XAML or code-behind.
            
Public Sub SetExtent(ByVal myMap As ESRI.ArcGIS.Client.Map)
  
  ' Clear out any existing layers.
  myMap.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"
  myMap.Layers.Add(myArcGISTiledMapServiceLayer)
  
  ' Set the initial Extent of the Map (Continental US).
  Dim myEnvelope As New ESRI.ArcGIS.Client.Geometry.Envelope
  myEnvelope.XMin = -130
  myEnvelope.YMin = 5
  myEnvelope.XMax = -70
  myEnvelope.YMax = 65
  myMap.Extent = myEnvelope
  
End Sub
  
Public Sub GetExtent(ByVal mymap As ESRI.ArcGIS.Client.Map)
  
  ' Extent (Read/Write)
  ' Returns Nothing/null if no layers added to Map.
  Dim myEnvelope As New ESRI.ArcGIS.Client.Geometry.Envelope
  myEnvelope = mymap.Extent
  
  ' Return the Map.Extent in a MessageBox
  Dim myString As String = Nothing
  If myEnvelope IsNot Nothing Then
      myString = "The Map.Extent is:" + vbCrLf + _
      "XMin: " + mymap.Extent.XMin.ToString + vbCrLf + _
      "YMin: " + mymap.Extent.YMin.ToString + vbCrLf + _
      "XMax: " + mymap.Extent.XMax.ToString + vbCrLf + _
      "YMax:" + mymap.Extent.YMax.ToString
  Else
      myString = "No Map.Extent set."
  End If
  System.Windows.MessageBox.Show(mystring)
End Sub