This .NET class wraps the AcDbSortentsTable ObjectARX class. 

DrawOrderTable is the persistent container for draw order information. It resides in the extension dictionary of an associated BlockTableRecord under the key ACAD_SORTENTS. 

DrawOrderTable contains a set of object ID/handle pairs. The object ID is that of the entity to be drawn, and the handle is that of an entity in the block table record (usually but not always different from the associated object ID), which represents the position in the draw order. Entities are appended to a block table record in order of ascending handle value; in other words, the higher the handle value, the later it appears in a block table record. When it's time to draw entities in a block table record, an iterator goes through the block table record in append order. At each entity, the handle value is obtained and used to query into the sortents table. If there is a match, the object ID associated with the handle value in the sortents table is drawn. If there is no match in the sortents table, then the entity at the iterator position is drawn in its "natural" order. 

When the draw order of entities is modified, many of the entries in the sortents table may be modified. For example, a block table record has five entities with the following handles (usually represented as strings representing hexadecimal numbers): 4A, 4B, 4C, 4D, 4E. These handles appear in ascending order. When an application iterates over the entities in a block table record in the default direction, the handle value always increases from one entity to the next. 

To draw the last entity in the space first (or "behind" the others), five entries in the sortents table must be made, as follows: 

The order of the entries (represented as a row in the preceding table) is irrelevant; draw order processing ends up sorting the entries by the draw order handle when performing the draw. In other words, in a DXF file, the table entries might appear in the following order, but the resultant draw order is identical: 

As another example, the last entity in the space is moved "under" the next-to-last entity in the space, but the rest of the entities are drawn in "natural" order. In that case, the sortents table would only need two entries, as follows: 

Adding new entities to the block table record with an implicit draw order of "last" requires no new entry in the sortents table.

Autodesk.AutoCAD.DatabaseServices.DBObject
    Autodesk.AutoCAD.DatabaseServices.DrawOrderTable

Public Class DrawOrderTable
Inherits DBObject

public class DrawOrderTable : DBObject;