c# - Check for missing elements while using LINQ to XML -

i trying data xml. below code gets data xdocument , return list<t>.

however, p.element("sponsor") can null. how can check null values

var atclauselist = doc.descendants(clause_group_tag).descendants(at_clause_tag).select(p => new atclause()             {                 clausenumber = (string)p.element("number"),                 sponsors = p.element("sponsor").elements(sponsor_tag).select(y => y.value)                                        .tolist(),                 page = p.element("sponsor").element("aitem").element("amendtext").element("page").elementvaluenull(),                 line = p.element("sponsor").element("aitem").element("amendtext").element("line").elementvaluenull(),                 linetext = p.element("sponsor").element("aitem").element("amendtext").nodes().oftype<xtext>().firstordefault().xtextvaluenull(),                 italictext = p.element("sponsor").element("aitem").element("amendtext").element("italic").elementvaluenull(),                 paralist = p.element("sponsor").element("aitem").element("amendtext").elements("para").select(l => new para                     {                         paratext = (string)l,                         number = ((system.xml.linq.xelement)(l)).attributevaluenull("number"),                         quote = ((system.xml.linq.xelement)(l)).attributevaluenull("quote"),                     }                     ).tolist()             }).tolist(); 

move code out of object initializer, , add logic it:

var atclauselist = new list<atclause>();  foreach(var item in doc.descendants(clause_group_tag).descendants(at_clause_tag)) {     var atclause = new atclause();      atclause.clausenumber = (string)item.element("number");      var sponsor = item.element("sponsor");      if (sponsor != null)     {            atclause.sponsors = sponsor.elements(sponsor_tag).select(y => y.value).tolist();            atclause.page = sponsor.element("aitem").element("amendtext").element("page").elementvaluenull();            atclause.line = sponsor.element("aitem").element("amendtext").element("line").elementvaluenull();            atclause.linetext = sponsor.element("aitem").element("amendtext").nodes().oftype<xtext>().firstordefault().xtextvaluenull();            atclause.italictext = sponsor.element("aitem").element("amendtext").element("italic").elementvaluenull();            atclause.paralist = sponsor.element("aitem").element("amendtext").elements("para").select(l => new para            {                 paratext = (string)l,                 number = ((system.xml.linq.xelement)(l)).attributevaluenull("number"),                 quote = ((system.xml.linq.xelement)(l)).attributevaluenull("quote"),            }).tolist();              atclauselist.add(atclause);      }