读写扩展数据

写扩展数据，其中使用upgradeOpen()函数对象的打开方式变为写方式

static void lzxARX_AcDbDatabaseAddXData(void)
    {
        //获得对象
        AcDbObject* pObj = selectObject(AcDb::kForRead);

        if (!pObj)
        {
            acutPrintf(L"Error selecting object\n");
            return;
        }

        //获得将要添加到扩展数据中的应用程序名和字符串
        ACHAR appName[132], resString[200];
        appName[0] = resString[0] = '\0';

        acedGetString(NULL, L"Enter application name:",appName);
        acedGetString(NULL,L"Enter string to be addec:", resString);

        struct resbuf *pRb, *pTemp;

        //添加扩展数据
        pRb = pObj->xData(appName);

        if (pRb != NULL)
        {
            //如果对象上已经有扩展数据，则到链表层
            for (pTemp = pRb; pTemp->rbnext != NULL; pTemp = pTemp->rbnext)
            {
                
            }
        }
        else
        {
            //如果扩展数据不存在，则注册该应用程序，然后将应用程序名添加到链表的首部
            acdbRegApp(appName);

            pRb = acutNewRb(AcDb::kDxfRegAppName);
            pTemp = pRb;
            pTemp->resval.rstring = (ACHAR *)malloc(_tcslen(appName)+1);
            _tcscpy(pTemp->resval.rstring, appName);
        }

        //将用户指定的数据添加到扩展数据中
        pTemp->rbnext = acutNewRb(AcDb::kDxfXdAsciiString);
        pTemp = pTemp->rbnext;
        pTemp->resval.rstring = (ACHAR *)malloc(_tcslen(resString)+1);
        _tcscpy(pTemp->resval.rstring, resString);

        //下面使用upgradeOpen()函数对象的打开方式变为写方式
        pObj->upgradeOpen();
        pObj->setXData(pRb);
        pObj->close();
        acutRelRb(pRb);
    }

读取扩展数据

    static void lzxARX_AcDbDatabasePrintXData(void)
    {
        //选择对象并打开该该对象
        AcDbObject* pObj;
        if ((pObj = selectObject(AcDb::kForRead)) == NULL)
        {
            return;
        }

        //获得应用程序名称
        ACHAR appName[133];
        if (acedGetString(NULL,L"\nEnter the desired Xdata application name:", appName) != RTNORM)
        {
            return;
        }

        //获得对应于应用程序名称的扩展数据
        struct resbuf *pRb;
        pRb = pObj->xData(appName);

        if (pRb!=NULL)
        {
            //如果存在数据，则打印扩展数据
            printList(pRb);
            acutRelRb(pRb);
        }
        else
        {
            //没有扩展数据
            acutPrintf(L"\nNo xdata for this sppname");
        }
        pObj->close();
    }

下面是两个自定义函数

    //打印链表中的数据
    static void printList(struct resbuf* pRb)
    {
        int rt, i;
        ACHAR buf[133];

        //对链表中数据的类型进行判断
        for(i = 0; pRb != NULL; i++, pRb = pRb->rbnext)
        {
            if (pRb->restype < 1010)
            {
                rt = RTSTR;
            }
            else if (pRb->restype < 1040)
            {
                rt = RT3DPOINT;
            }
            else if (pRb->restype < 1060)
            {
                rt = RTREAL;
            }
            else if (pRb->restype < 1071)
            {
                rt = RTSHORT;
            }
            else if (pRb->restype = 1071)
            {
                rt = RTLONG;
            }
            else
            {
                //未知类型
                rt = pRb->restype;
            }

            //对不同类型数据进行处理
            switch(rt)
            {
            //短整型数据
            case RTSHORT:
                if (pRb->restype == RTSHORT)
                {
                    acutPrintf(L"RTSHORT : %d\n", pRb->resval.rint);
                }
                else
                {
                    acutPrintf(L"(%d . %d)\n",pRb->restype,pRb->resval.rint);
                }
                break;

            //实型数据
            case RTREAL:
                if (pRb->restype == RTREAL)
                {
                    acutPrintf(L"RTREAL : %0.3f\n", pRb->resval.rreal);
                }
                else
                {
                    acutPrintf(L"(%d . %0.3f)\n",pRb->restype,pRb->resval.rreal);
                }
                break;

            //这符串型数据
            case RTSTR:
                if (pRb->restype == RTSTR)
                {
                    acutPrintf(L"RTSTR : %s\n", pRb->resval.rstring);
                }
                else
                {
                    acutPrintf(L"(%d . \"%s\")\n", pRb->restype, pRb->resval.rstring);
                }
                break;

            //三维点
            case RT3DPOINT:
                if (pRb->restype == RT3DPOINT)
                {
                    acutPrintf(L"RT3DPOINT : %0.3f, %0.3f, %0.3f,\n", 
                        pRb->resval.rpoint[X],
                        pRb->resval.rpoint[Y],
                        pRb->resval.rpoint[Z]);
                }
                else
                {
                    acutPrintf(L"(%d %0.3f, %0.3f, %0.3f,\n", 
                        pRb->restype,
                        pRb->resval.rpoint[X],
                        pRb->resval.rpoint[Y],
                        pRb->resval.rpoint[Z]);
                }
                break;

            //长整型
            case RTLONG:
                acutPrintf(L"RTLONG : %d\n", pRb->resval.rlong);
                break;
            }

            //数据处理完成
            if ((i == 23) && (pRb->rbnext != NULL))
            {
                i = 0;
                acedGetString(0, L"Press <ENTER> to continue...", buf);
            }
        }
    }

    //获得对象并打开该对象的函数
    static AcDbObject* selectObject(AcDb::OpenMode openMode)
    {
        //提示用户选择实体
        int ss;
        ads_name en;
        ads_point pt;
        ss = acedEntSel(L"\nSelect an Entity: ", en, pt);

        AcDbObjectId eId;

        //实体选择错误
        if(ss != RTNORM)
        {
            acutPrintf(L"Selection error, Return Code = %d\n", ss);
            return NULL;
        }

        //通过ads_name获得对象ＩＤ
        Acad::ErrorStatus retStat;
        retStat = acdbGetObjectId(eId, en);
        if (retStat != Acad::eOk)
        {
            //没胡获得对象ＩＤ
            acutPrintf(L"\nacadGelObjectId failed");
            acutPrintf(L"\nen == (%lx,%lx), restStat == %d\n", en[0], en[1], eId);
            return NULL;
        }

        AcDbObject* obj;

        //打开对象
        if ((retStat = acdbOpenObject(obj, eId, openMode)) != Acad::eOk)
        {
            acutPrintf(L"acdbOpenEntiy failed: ename: (%lx,%lx), mode:%d retStat:%d", en[0], en[1], openMode, retStat);
            return NULL;
        }

        //返回对象指针
        return obj;
    }