What is namespace that includes: esriGeoDatabase.Fields ?

[TaiBui]

Hi,

Are there anyone know what is namespace that includes: esriGeoDatabase.Fields ?

I try to use below namspace, but not successful:

using ESRI.ArcGIS.Geodatabase;
using ESRI.ArcGIS.DataSourcesFile;
using ESRI.ArcGIS.esriSystem;
using ESRI.ArcGIS.Geometry;

Thanks and regards,

[RichardWatson]

http://resources.arcgis.com/en/help/arcobjects-net/componenthelp/0025/0025000000n9000000.htm