LINQ: How to sort the items of a recursive tree structure?

Asked Mar 08 '18 at 08:30

Active Mar 08 '18 at 08:30

Viewed 65 times

I have this entity model:

public class ProductCategory
{
    public int Id { get; set; }
    public string Title { get; set; }
    public int SortOrder { get; set; }
    public int? ParentId { get; set; }
    public ProductCategory ParentCategory { get; set; }
    public ICollection<ProductCategory> Children { get; set; } = new List<ProductCategory>();
}

How can I write a LINQ query that sorts a recursive tree structure of categories correctly? This is what I have now:

var categories = _context.ProductCategories
                        .Include(e => e.Children).ToList().OrderBy(o => o.SortOrder)
                        .Where(e => e.ParentId == null)
                        .OrderBy(o => o.SortOrder);

The root categories (with ParentId == null are correctly sorted, but the children are not.

asked Mar 08 '18 at 08:30

Stian

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What do you mean by recursive? That each ProductCategory has a list of child categories? – Gil Grossman Mar 08 '18 at 08:33
A dupe from 2013, I don't think anything has changed. You cannot filter or sort a Details list. – H H Mar 08 '18 at 08:38
@GilGrossman Yes. And each child can have children too. Hence the `ParentId`-field in the model. – Stian Mar 08 '18 at 08:48

LINQ: How to sort the items of a recursive tree structure?

0 Answers0