此代码能实现对二维工程图DWG格式文件进行读取并显示。-This code can achieve two-dimensional drawing of the DWG file format to read and display.

Open DWG 示例，比较难找的资料，直接脱离CAD软件单独操作CAD文件，开发自己的CAD程序-Open DWG example, more difficult to find the information directly from the individual operating CAD files CAD software, CAD programs to develop their own

openDwg测试代码ReadDWG，有很大的参考意义(openDwg test code ReadDWG,that may helpful for you)