This .NET class wraps the AcDbBlockTable ObjectARX class, which is the symbol table for BlockTableRecords, which represent block definitions within a drawing database.

Autodesk.AutoCAD.DatabaseServices.DBObject
    Autodesk.AutoCAD.DatabaseServices.SymbolTable
        Autodesk.AutoCAD.DatabaseServices.BlockTable

Public sealed Class BlockTable
Inherits SymbolTable
Inherits IEnumerable

public sealed class BlockTable : SymbolTable, IEnumerable;