In addition to the graphical objects used by AutoCAD, there are several types of nongraphical objects stored in a drawing database. These objects have descriptive designations associated with them. For example, blocks, layers, groups, and dimension styles all have a name assigned to them and in most cases can be renamed. The names of symbol table records are displayed in the user interface of AutoCAD, while the object id of an object is used to reference the object in most cases throughout the .NET API.
除了 AutoCAD 所使用的图形对象之外，图形数据库中还保存了几种非图形对象。这些对象都具有描述性的名称。例如所有的块、图层、编组和标注样式都指定了名字，并且大部分情况下都可以重命名。符号表记录的名字是被用来显示在 AutoCAD 的用户界面上的，而对象的 ObjectID 在 的大多数情况下用于在整个.NET API 中引用对象。
For example, the object id of a LayerTableRecord object is assigned to a graphical object’s Layer property and not the actual name that is assigned to the LayerTableRecord. However, the object id of a LayerTableRecord object can be obtained from the Layer table using the name of the layer you want to access.
例如，LayerTableRecord 对象的 ObjectID 被指定给一个图形对象的 Layer 属性而非指定给 LayerTableRecord 的真实名字。可是，利用想访问的层的命令可以 从层表中获得 LayerTableRecord 的 ObjectID。
