Question

I’m trying to order the values in a related table using LINQ to SQL.

I have 2 tables. Menu and MenuSection. They are related one to many on Menu.MenuId == MenuSection.MenuId

Currently, I’m pulling this information using the following query

var menus = from m in _context.Menus                        
                    select m;

This gets fed into an ASP.NET MVC page and works fine.

I’d like to be able to sort the data the column MenuSection.Order

I’ve tried doing this:

var menus = from m in _context.Menus 
                join ms in _context.MenuSections on m.MenuId equals ms.MenuId
                orderby ms.Order ascending select m;

But it’s bringing back a set of data that is incorrect. It displays repeated Menu information.

EDIT: To clarify what i’m expecting the data shoud be:

There are x Menu’s in Menu.

Each Menu has many MenuSection’s

I’d like to list out each Menu and their related MenuSection.
The MenuSections need to be in order based on MenuSection.Order

Menu 1
- MenuSection 1, Order = 1
- MenuSection 3, Order = 2
Menu 2
- MenuSection 4, Order = 1
- MenuSection 2, Order = 2

Answer 1

Round 3: That last revision to the question clarifies it a lot. It sounds like what you really need is a group-by. Those are harder to get right without the IntelliSense but I’ll try my best:

var groupings =
    from m in _context.Menus
    orderby m.Foo
    from ms in m.MenuSections
    orderby ms.Order
    group ms by m;

foreach (var group in groupings)
{
    Menu menu = group.Key;
    // use the Menu

    foreach (MenuSection ms in group)
    {
        // use the MenuSection
    }
}

Now I added an extra orderby m.Foo where Foo is some property that I think you might want on Menu. Otherwise you aren’t guaranteed to know the order of the top level menus.

Also note what I was saying earlier that the m.MenuSections is really a helper that is similar to from ms in _context.MenuSections where ms.MenuId == m.MenuId.