c# - Add XElement only if value exists -

i'm creating xdocument using linq-to-xml, this:

order order = getorder();  xdocument doc = new xdocument(     new xelement("purchaseorder",         new xelement("name", order.name),         new xelement("address", order.address),         new xelement("shipper", order.shipper)     ) ); 

so order not have shipper, null. in case, don't want include shipper element @ all.

how can inline in code when creating doc?

i form xml in parts instead of forming of @ once. (easier read, easier debug)

xdocument doc = new xdocument();  var order = new xelement("purchaseorder",                 new xelement("name", order.name),                 new xelement("address", order.address));  if(order.shipper!=null) order.add(new xelement("shipper", order.shipper));  doc.add(order);