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C# Help with Recursive function - Generic List

Hi..
I have Generic list of objects. The object contains a Parent and Children object that can contain additional objects with children. The List<> is bound to a treeview.

I need to write a recursive method that will loop through all the objects and there children and return the names of the objects..
Any ideas?
thx

Todd Gerbert

Have a look at this post: http:Q_26610392#a34121687

The example I posted in that question uses a DataTable as the source, but could just as easily be used with a List<> of objects.

Todd Gerbert

I did the link wrong...try this: http:Q_26610392.html#a34121687

Avodah

Here is a console application that does what you want.

DaTribe

class Program
{
	class Item
	{
		public string Name { get; set; }
		public List<Item> Children { get; set; }

		public Item()
		{
			Children = new List<Item>();
		}
	}

	static void Main(string[] args)
	{
		Item parent = new Item() { Name = "1"};
		parent.Children.Add(new Item() { Name = "2"});
		parent.Children.Add(new Item() { Name = "" });

		var names = GetNames(parent);

		Console.ReadKey();
	}

	static List<string> GetNames(Item item)
	{
		List<string> names = new List<string>();
		names.Add(item.Name);

		foreach(var child in item.Children)
		{
			var childNames = GetNames(child);
			names.AddRange(childNames);
		}

		return names;
	}
}

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JElster

ASKER

Hi..
If I include a propertiy called IsSelected.
How can I only return those with the IsSelected = true:

thanks

ASKER CERTIFIED SOLUTION

Avodah

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Avodah

Actually this version does not work

item.Children.Where(x => x.IsSelected)

This will exclude children further down the tree that are selected if their parent is not selected.

DaTribe

JElster

ASKER

Yeah... I just tried it... any ideas?
thanks

Avodah

I gave you two ideas before:

if(item.IsSelected)
names.Add(item.Name);

This one works!

DaTribe

JElster

ASKER

i only got one.......

static List<string> GetNames(Item item)
{
      List<string> names = new List<string>();

// You can do this
if(item.IsSelected)
       names.Add(item.Name);

// You can also do this -- but this excludes checking
// the parent item
      foreach(var child in item.Children.Where(x => x.IsSelected))
      {
            var childNames = GetNames(child);
            names.AddRange(childNames);
      }

      return names;
}

Avodah

Ok I see where the confusion lies. In that one post it was either or rather than implementing both solutions.

1. if(item.IsSelected)
names.Add(item.Name);

or

2. foreach(var child in item.Children.Where(x => x.IsSelected))

DaTribe