AutoCAD 2012 帮助 |  |
AutoCAD 2012 帮助 | |
Several AutoLISP functions are provided to handle extended data (xdata), which is created by applications written with ObjectARX or AutoLISP. If an entity contains xdata, it follows the entity's regular definition data.
You can retrieve an entity's extended data by calling entget. The entget function retrieves an entity's regular definition data and the xdata for those applications specified in the entget call.
When xdata is retrieved with entget, the beginning of extended data is indicated by a -3 code. The -3 code is in a list that precedes the first 1001 group. The 1001 group contains the application name of the first application retrieved, as shown in the table and as described in the topics in this section.
| Using AutoLISP to Manipulate AutoCAD Objects |  | |
| Selection Set Handling | ||
| Object Handling | ||
| Extended Data - xdata | ||
| Organization of Extended Data | ||
| Registration of an Application | ||
| Retrieval of Extended Data | ||
| Attachment of Extended Data to an Entity | ||
| Management of Extended Data Memory Use | ||
| Handles in Extended Data | ||
| Xrecord Objects | ||
| Symbol Table and Dictionary Access | ||
