The default area of interest for the layer. 
[Visual Basic .NET]
Public ReadOnly Property AreaOfInterest As IEnvelope
[C#]
public IEnvelope AreaOfInterest {get;}
[C++]
HRESULT get_AreaOfInterest(
  IEnvelope** aoi
);
[C++]
Parameters
aoi [out, retval]
  aoi is a parameter of type IEnvelope
 
Product Availability
Available with ArcGIS Engine, ArcGIS Desktop, and ArcGIS Server.
Remarks
Returns the spatial-referenced extent of the layer. 
See Also
ILayer Interface
.NET Snippets
Zoom to Globe Layer | 
.NET Samples
Create a command by inheriting from BaseCommand (Code Files:  
ZoomToLayer) | 
Create a custom selection extension by extending ArcObjects (Code Files:  
ZoomToLayerMultiItem) | 
Custom UI elements using add-ins (Code Files:  
ZoomToLayerButton) | 
.NET Related Topics
Create a command by inheriting from BaseCommand | 
How to create dynamic menu commands using a MultiItem | 
Persisting cache information for use in dynamic display |