x++ code for how to change common table to required table at run time in AX 2012

common _target; //Declaration

   dictTable = new DictTable(tableNum(VendInvoiceInfoLine));

            _target = dictTable.makeRecord();// here now common buffer is converted to VendInvoiceInfoLine 

            //below I'm using VendInvoiceInfoLine .initfrompurchline() through _target 

            _target.initFromPurchLine(purchline); 

            _target.(fieldnum(VendInvoiceInfoLine,defaultdimension)) = purchline.DefaultDimension;

            if(entity.ReceiveNow)

            {

                 //Assigning value on dixf insert update methoad

                _target.(fieldnum(VendInvoiceInfoLine, Receivenow)) = entity.ReceiveNow; 

                _target.(fieldnum(VendInvoiceInfoLine, LineAmount)) = entity.ReceiveNow * _target.(fieldnum(VendInvoiceInfoLine,PurchPrice));

            }

reffred link: http://dotnetxperience.blogspot.in/2012/04/dynamics-ax-get-table-buffer-common.html