How to flatten nested objects with linq expression
I am trying to flatten nested objects like this:
public class Book
{
public string Name { get; set; }
public IList<Chapter> Chapters { get; set; }
}
public class Chapter
{
public string Name { get; set; }
public IList<Page> Pages { get; set; }
}
public class Page
{
public string Name { get; set; }
}
Let me make an example. This is the data I have
Book: Pro Linq
{
Chapter 1: Hello Linq
{
Page 1,
Page 2,
Page 3
},
Chapter 2: C# Language enhancements
{
Page 4
},
}
The result I am looking for is the following flat list:
"Pro Linq", "Hello Linq", "Page 1"
"Pro Linq", "Hello Linq", "Page 2"
"Pro Linq", "Hello Linq", "Page 3"
"Pro Linq", "C# Language enhancements", "Page 4"
How coul开发者_StackOverflow社区d I accomplish this? I could do it with a select new but I've been told that a SelectMany would be enough.
myBooks.SelectMany(b => b.Chapters
.SelectMany(c => c.Pages
.Select(p => b.Name + ", " + c.Name + ", " + p.Name)));
Assuming books
is a List of Book:
var r = from b in books
from c in b.Chapters
from p in c.Pages
select new {BookName = b.Name, ChapterName = c.Name, PageName = p.Name};
myBooks.SelectMany(b => b.Chapters
.SelectMany(c => c.Pages
.Select(p => new
{
BookName = b.Name ,
ChapterName = c.Name ,
PageName = p.Name
});
I was trying to do this as well, and from Yuriy's comments and messing with linqPad I have this..
Note that I don't have books, chapters, pages, I have person (books), companyPerson (chapters) and companies (pages)
from person in Person
join companyPerson in CompanyPerson on person.Id equals companyPerson.PersonId into companyPersonGroups
from companyPerson in companyPersonGroups.DefaultIfEmpty()
select new
{
ContactPerson = person,
ContactCompany = companyPerson.Company
};
or
Person
.GroupJoin (
CompanyPerson,
person => person.Id,
companyPerson => companyPerson.PersonId,
(person, companyPersonGroups) =>
new
{
person = person,
companyPersonGroups = companyPersonGroups
}
)
.SelectMany (
temp0 => temp0.companyPersonGroups.DefaultIfEmpty (),
(temp0, companyPerson) =>
new
{
ContactPerson = temp0.person,
ContactCompany = companyPerson.Company
}
)
Ref site I used: http://odetocode.com/blogs/scott/archive/2008/03/25/inner-outer-lets-all-join-together-with-linq.aspx
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