Question

How do I embed the ordinal number of element as its attribute in this linq query.

var AllSections = from s in xmlDoc.Descendants("section")
                      select new
                      {
                          id = s.Attribute("id").Value,
                          themeTitle = s.Element("themeTitle").Value,
                          themeText = s.Element("themeText").Value,
                          objects = (from  a in AllObjects 
                                     join b in s.Descendants("object")
                                     on  a.Attribute("accessionNumber").Value equals
                                         b.Attribute("accessionNumber").Value
                                      //select a
                                      select new
                                       {
                                        //index = insert ordinal id/index of element

                                        ObjectTitle = a.Element("ObjectTitle").Value,
                                        ObjectText = a.Element("textentry").Value,


                                        }   
                                         )


                      };

Answer 1

@Jon Skeet gave you the appropriate overload of Select to use, and here is it in your query:

var AllSections = from s in xmlDoc.Descendants("section")
    select new
    {
        id = s.Attribute("id").Value,
        themeTitle = s.Element("themeTitle").Value,
        themeText = s.Element("themeText").Value,
        objects = (from a in AllObjects 
                   join b in s.Descendants("object")
                       on a.Attribute("accessionNumber").Value
                       equals b.Attribute("accessionNumber").Value
                   select a).Select((a, index) =>
                       new
                       {
                           Index = index,
                           ObjectTitle = a.Element("ObjectTitle").Value,
                           ObjectText = a.Element("textentry").Value,
                       })
    };