Default extension (without the dot).
[Visual Basic .NET] Public ReadOnly Property Extension As String
[C#] public string Extension {get;}
[C++]
HRESULT get_Extension(
BSTR* pVal
);
[C++]Parameters
pVal [out, retval] pVal is a parameter of type BSTR
Product Availability
Available with ArcGIS Engine, ArcGIS Desktop, and ArcGIS Server.