C＃-IEnumerable <> StackOverFlowException（AVLTree）

Question

I am having an issue with using IEnumerable<>

I am reading in a CSV File, I have my get/set methods sorted and I have tested my code before implementing IEnumerable<> and the Autos/Locals are displayed correctly.

I'm trying to display the CSV file's content within a DataGridView

foreach (Country country in avlTree)
                    {

                      displayCountriesDataGridView.Rows.Add(country.CountryName, country.GDPGrowth, country.Inflation, country.TradeBalance, country.HDIRank, country.TradingPartners);

                    }

And using an AVLTree and the InsertItem method I have wrote to append this data to the AVLTree

  avlTree.InsertItem(tempCountry);

This problem arises when I use:

class AVLTree<T> : BSTree<T>, IEnumerable<Country> where T : IComparable

I have implemented the interfaces :

 public IEnumerator<Country> GetEnumerator()
        {

            return this.GetEnumerator();

            throw new NotImplementedException();
        }

        IEnumerator IEnumerable.GetEnumerator()
        {

            return GetEnumerator();
            throw new NotImplementedException();
        }


    }

However, no luck what-so-ever.

In the Locals, I get this output-

$exception {"Exception of type "System.StackOverflowException' was thrown"}

I get a red-cross and the name this with the value Unable to read memory

And Type Variables T has the value System.__Canon

I implemented IEnumerable<> in my Country class and no issues.

I just can't seem to understand what is causing this issue.

Could someone please offer some guidance or shed light on this matter.

Thank you.

EDIT - Implementation of my AVLTree

   class AVLTree<T> : BSTree<T>, IEnumerable<Country> where T : IComparable
    {

        Node<T> newRoot;



        public new void InsertItem(T item)
        {
            insertItem(item, ref root);
        }



        private void insertItem(T item, ref Node<T> tree)
        {
            if (tree == null)
            {
                tree = new Node<T>(item);
            }

            else if (item.CompareTo(tree.Data) < 0)
            {
                insertItem(item, ref tree.Left);
            }
            else if (item.CompareTo(tree.Data) > 0)
            {
                insertItem(item, ref tree.Right);
            }

            tree.BalanceFactor = Height(ref tree.Left) - Height(ref tree.Right);

            if (tree.BalanceFactor <= -2)
            {
                rotateLeft(ref tree);
            }
            if (tree.BalanceFactor >= 2)
            {
                rotateRight(ref tree);
            }
        }




        private void rotateRight(ref Node<T> tree)
        {
            if (tree.Left.BalanceFactor < 0)
            {
                rotateLeft(ref tree.Left);
            }
            newRoot = tree.Left;
            tree.Left = newRoot.Right;
            newRoot.Right = tree;
            tree = newRoot;

        }


        private void rotateLeft(ref Node<T> tree)
        {
            if (tree.Right.BalanceFactor > 0)
            {
                rotateRight(ref tree.Right);
            }

            newRoot = tree.Right;
            tree.Right = newRoot.Left;
            newRoot.Left = tree;
            tree = newRoot;

        }

        public IEnumerator<Country> GetEnumerator()
        {
            // Some iterator/loop which uses "yield return" for each item

        }


        IEnumerator IEnumerable.GetEnumerator()
        {
            return GetEnumerator();
        }

Answer 1

You need to actually implement an enumerator. Right now your implementation loops infinitely by calling itself -- no enumerator is returned.

public IEnumerator<Country> GetEnumerator()
{
    // Some iterator/loop which uses "yield return" for each item
    foreach (var item in items)
        yield return item;
}

IEnumerator IEnumerable.GetEnumerator()
{
    return GetEnumerator();
}