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Answer 1

+1 A:

Yeah. You have the right idea. If you need a two-directional hierarchy, I wouldn't use a multi-dimensional list... I would add a node to the tree and each node contains a parent and a collection of children.

You are on the right track.

Brian Genisio 2009-04-14 18:42:42

Answer 2

+1 A:

This is a fairly basic implementation of a tree, yes. If choose to make your collection for the children an IList or IEnumable or ArrayList, etc is up to you.

I would strongly suggest you build a generic implementation instead of one typed to your domain model, however that is up to you.

Chad Ruppert 2009-04-14 18:43:58

Thanks, in your second paragraph, you mean writing a generic CustomCollection<T>?

Joan Venge 2009-04-14 18:46:14

No, more Like Treenode<T> which contains TreeNode<T> Parent and IEnumerable<Treenode<T>> Children

Chad Ruppert 2009-04-14 18:50:02

Note that it only applies, as Lucero mentions in a post below, if all objects are of the same type or abstraction thereof.

Chad Ruppert 2009-04-14 18:54:42

Thanks, so like Node : BaseNode, Node Parent, IEnumerable<Node> Children ? If I do that, would the Parent/Children cast the actual class down?

Joan Venge 2009-04-14 19:24:28

Have two generic type parameters, one for branches, one for leaves.

Pete Kirkham 2009-04-14 19:28:25

That's very good advice. I tend to use trees where leaves can be branches, but that's entirely up to you.

Chad Ruppert 2009-04-14 19:46:23

If you use generics, you will have to have a non-generic base class (or an interface) which you also use as constraint.

Lucero 2009-04-15 10:33:21

Answer 3

+1 A:

If not all items are of the same type, I may use an abstract base class for a linked list and children collections in such a situation.

Lucero 2009-04-14 18:50:48

Thanks, so like Node : BaseNode, Node Parent, IEnumerable<Node> Children ? If I do that, would the Parent/Children cast the actual class down?

Joan Venge 2009-04-14 19:02:11

We,, I guess the children can be of different types. However, using generics, you could in fact have a strongly typed parent if necessary. But usually you just use the base class in this pattern.

Lucero 2009-04-15 10:31:21

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