LINQ - Is there a way to get element values after grouping without ForEach?

I have an Items table that contains a CategoryId field. This is an FK into a Categories table. I want to group my Items by CategoryId and return the Items and Categories.Name.

I know I can do this in C#:

var ItemsByCat = 
    from i in Items
    group i by i.CategoryId i开发者_JAVA百科nto g
    select g

foreach(var n in ItemsByCat)
{
    blah, blah
}

My question is - is there a way to get at the element values part of the grouping without having to iterate through with a loop? Something like:

from i in Items
group i by i.CategoryId into g
select new {
    CategoryID = g.Key,
    CategoryName = ???,
    Items = ???
}

Many thanks,

BK

---

I think this is what you're looking for:

from i in Items
group i by i.CategoryId into g
select new 
{
    CategoryID = g.Key,
    CategoryName = g.First().Category.Name,
    Items = g
}

EDIT: I hope this answers your question from the comments.

g is a collection of Items grouped by their CategoryId. Items in the select can be a projection including whatever subset of Item properties you require. Example:

from i in Items
group i by i.CategoryId into g
select new 
{
    CategoryID = g.Key,
    CategoryName = g.First().Category.Name,
    Items = g.Select(a => new{a.ItemID, a.ItemName})
}

---

What about joining the Categories table?

from i in Items
join c in Categories on i.CategoryId equals c.Id
group i by i.CategoryId into g
select new {
    CategoryID = g.Key,
    CategoryName = c.Name,
    Items = i
}

---

CategoryName should be i.Category.CategoryName //the name property

given you have the relationship setup properly.

The items should be the values of group by, not sure why you'd need to do it again.

---

Assuming you have a collection of Categories in a variable categories it would look like this:

var ItemsByCategory = 
  from i in items
  join c in categories on i.CategoryId equals c.Id
  group i by i.CategoryId into g
  select new {
    CategoryId=g.Key,
    CategoryName=c.Name,
    Items=g.Items
}