How to build a hierarchy with use Linq to object?

Question

I have a list of data structures:

        public List Personals()
        {
            return new List
                {
            


        

Answer 1

Same as above only this code checks for the case that your root node has a ParentID that matches its own ID.

    public void SomeMethod()
    {
        // here you get your `list`
        var tree = GetTree(list, 0);
    }

    public List<Tree> GetTree(List<Personal> list, int parent)
    {
        return list.Where(x => x.ParentId == parent).Select(x => new Tree
        {
            Id = x.Id,
            Name = x.Name,
            List = x.ParentId != x.Id ? GetTree(list, x.Id) : new List<Tree>()
        }).ToList();
    }

Answer 2

You should use recursion:

public void SomeMethod() {
     // here you get your `list`
     var tree = GetTree(list, 0);
}

public List<Tree> GetTree(List<Personal> list, int parent) {
    return list.Where(x => x.ParentId == parent).Select(x => new Tree {
        Id = x.Id,
        Name = x.Name,
        List = GetTree(list, x.Id)
   }).ToList();
}