删除外部dwg中指定的块定义

void CBlockUtil::DeleteBlockDefFormOtherDwg(const TCHAR* fileName, const TCHAR* blkDefName)
{
    // 使用_SH_DENYNO参数打开图形(只读打开)，允许其它用户读写该文件
    AcDbDatabase* pSourceDwg = new AcDbDatabase(Adesk::kFalse);
    Acad::ErrorStatus es = pSourceDwg->readDwgFile(fileName);
    if (es != Acad::eOk)
    {
        delete pSourceDwg;
        pSourceDwg = NULL;
        acutPrintf(TEXT("\n读入dwg图形错误, 图形名称: %s"), fileName);
        return;
    }
    // 打开外部图形数据库的块表，寻找给定名称的块表记录
    AcDbBlockTable* pBlkTable = NULL;
    es = pSourceDwg->getBlockTable(pBlkTable, AcDb::kForWrite);
    AcDbBlockTableRecord *pBlkTabRcd;
    CString strBlkDef(blkDefName);
    if (pBlkTable->has(strBlkDef))
    {
        pBlkTable->getAt(blkDefName, pBlkTabRcd, ZcDb::kForWrite);
        es = pBlkTabRcd->erase();    
    }
    else
    {
        acutPrintf(_T("\n在当前文件中不存在该块表！"));
        pBlkTable->close();
        delete pSourceDwg;
        pSourceDwg = NULL;
        return;
    }    
    pBlkTable->close();
    pBlkTabRcd->close();
        //保存更改后的数据库，这里一定不能少这句
    es=pSourceDwg->saveAs(fileName);
    delete pSourceDwg;
    pSourceDwg = NULL;
}

    AcDbBlockTable *pBlkTab;
    acdbHostApplicationServices()->workingDatabase()
        ->getBlockTable(pBlkTab, ZcDb::kForWrite);
    CString strBlk = _T("as");
    AcDbBlockTableRecord *pBlkTabRcd;
    if (pBlkTab->has(strBlk))
    {
        pBlkTab->getAt(strBlk, pBlkTabRcd, ZcDb::kForWrite);
        pBlkTabRcd->erase();
    }
    else
    {
        return;
    }
    pBlkTab->close();
    pBlkTabRcd->close();