This .NET class wraps the AcDbField ObjectARX class. 

It represents a field. The field can evaluate to one of the supported data types. The field object acts as a container to store the field expression, evaluated result, and other data. An evaluator is required for evaluating the field.

Autodesk.AutoCAD.DatabaseServices.DBObject
    Autodesk.AutoCAD.DatabaseServices.Field

Public Class Field
Inherits DBObject

public class Field : DBObject;