The Assoc2dConstraintGroup class represents a set of geometric constraint relations between subentities of geometric entities. All the geometries must lie in a single plane. 

The Assoc2dConstraintGroup object owns the constraints that are derived from the GeometricalConstraint class, and "proxies" of the constrained geometried, derived from ConstrainedGeometry class. ConstrainedGeometries often refer to subentities of AutoCAD entities and the Assoc2dConstraintGroup owns AssocGeomDepedencies on these entities. It also owns AssocValueDependencies on the AssocVariables that are the values of dimensional constraints (represented by classes derived from ExplicitConstraint). 

If the dimensional constraint has a graphical representation, such as in the form of a Dimension entity, the ExplicitConstraint also owns the AssocDependency owning an object derived from the AssocDimDependencyBody that facilitates the interaction between the ExplicitConstraint, the AssocVariable keeping the value of the dimensional constraint, and the Dimension (or other object/entity) that serves as a graphical representation of the dimensional constraint. 

The evaluate() method of this action takes the current properties of the referenced geometries and the current values of the variables referenced by ExplicitConstraints. Then it invokes a constraint solver that finds new positions and shapes of the constrained geometries so that they satisfy the constraints. Finally the referenced geometries are updated to their new positions and shapes. The evaluate method call may fail if a solution satisfying all the constraints can not be found.

Autodesk.AutoCAD.DatabaseServices.DBObject
    Autodesk.AutoCAD.DatabaseServices.AssocAction
        Autodesk.AutoCAD.DatabaseServices.Assoc2dConstraintGroup

Public Class Assoc2dConstraintGroup
Inherits AssocAction

public class Assoc2dConstraintGroup : AssocAction;