Retrieving Element from XML with LINQ

Question

I have the following XML

<Group>
    <Id>2</Id>
    <GroupName>Fizzy Drinks</GroupName>
    <DateCreated>0001-01-01T00:00:00</DateCreated>
    <DateModified>0001-01-01T00:00:00</DateModified>
    <Person>
      <PersonId>78</PersonId>
      <PersonName>Francesca</PersonName>
      <PersonSurname>Andrews</PersonSurname>
      <PersonAge>59</PersonAge>
    </Person>
    <Products>
      <ProductId>2</ProductId>
      <ProductName>Oranges</ProductName>
      <CategoryId>4</CategoryId>
      <CategoryName></CategoryName>
      <SubCategoryId>7</SubCategoryId>
      <SubCategoryName>Bread</SubCategoryName>
    </Products>
    <Products>
      <ProductId>12</ProductId>
      <ProductName>Pepsi</ProductName>
      <CategoryId>4</CategoryId>
      <CategoryName></CategoryName>
      <SubCategoryId>8</SubCategoryId>
      <SubCategoryName>Dairy</SubCategoryName>
    </Products>
    <Products>
      <ProductId>14</ProductId>
      <ProductName>Multiwheat Bread</ProductName>
      <CategoryId>4</CategoryId>
      <CategoryName></CategoryName>
      <SubCategoryId>7</SubCategoryId>
      <SubCategoryName>Bread</SubCategoryName>
    </Products>
</Group>

And I wish to retreive the following inside a Group object.

I have the following code :-

            foreach (XElement xe in xdoc.Descendants("Group"))
        {
            int id = Convert.ToInt32(xe.Element("Id").Value);

            var group = from g in xdoc.Descendants("Group")
                        where (int)g.Element("Id") == id // filtering groups here
                        select new Group
                        {
                            Id = (int)g.Element("Id"),
                            GroupName = (string)g.Element("GroupName"),
                            DateCreated = (DateTime)g.Element("DateCreated"),
                            DateModified = (DateTime)g.Element("DateModified"),
                            Person = from d in g.Descendants("Person")
                                     select new Person
                                         {
                                             Id = (int)d.Element("PersonId"),
                                             Name = (string)d.Element("PersonName"),
                                             Surname = (string)d.Element("PersonSurname"),
                                             Age = (int)d.Element("PersonAge"),
                                         },

                            PersonId = (int)g.Element("PersonId"),
                            PersonName = (string)g.Element("PersonName"),
                            PersonSurname = (string)g.Element("PersonSurname"),
                            PersonAge = (int)g.Element("PersonAge"),
                            Products = g.Elements("Products")
                                .Select(p => new Product
                                {
                                    Id = (int)p.Element("ProductId"),
                                    ProductName = (string)p.Element("ProductName")
                                }).ToList()
                        };

            foreach (var g in group)
            {
                GroupList.Add(g);
            }

        }

However I am getting an error since the Person is not IEnumerable. However since I will only ever have 1 person per group, I do not wish to make it IEnumerable. Is there a way around this?

Thanks for your help and time

Answer 1

It's better do declare new range variable which will hold <Person> element and use it later

var group = from g in xdoc.Descendants("Group")
            let person = g.Element("Person") // here
            where (int)g.Element("Id") == id
            select new Group {
               ...
            }

And use it:

 Person = new Person {
            Id = (int)person.Element("PersonId"),
            Name = (string)person.Element("PersonName"),
            Surname = (string)person.Element("PersonSurname"),
            Age = (int)person.Element("PersonAge")
          },

You can also add null check if it is possible that there is no person element in your xml:

 Person = (person == null) ? null : 
           new Person {
              Id = (int)person.Element("PersonId"),
              Name = (string)person.Element("PersonName"),
              Surname = (string)person.Element("PersonSurname"),
              Age = (int)person.Element("PersonAge")
           },

Answer 2

It sounds like you could do:

Person = (from d in g.Elements("Person")
          select new Person
          {
              Id = (int)d.Element("PersonId"),
              Name = (string)d.Element("PersonName"),
              Surname = (string)d.Element("PersonSurname"),
              Age = (int)d.Element("PersonAge"),
          }).First()

but it would be better to write:

Person = Person.FromXElement(g.Element("Person"))

where FromXElement is a static method in Person like this:

public static Person FromXElement(XElement element)
{
    return new Person
    {
        Id = (int) element.Element("PersonId"),
        Name = (string) element.Element("PersonName"),
        Surname = (string) element.Element("PersonSurname"),
        Age = (int) element.Element("PersonAge")
    };
}

That way your query will be a lot clearer.