merge sort

private void textBox1_KeyPress(object sender, KeyPressEventArgs e)
        {
            int i = 0;

            List<int> lst = new List<int>();
            if (e.KeyChar == Convert.ToChar(Keys.Enter) && i < 10)
            {
                lst.Add(int.Parse(textBox1.Text));
                textBox1.Text = "";
                i++;

            }

        }

private void button1_Click(object sender, EventArgs e)
       {

           List<int> lst = new List<int>();
           int[] array = lst.ToArray();

           DoSort(array);


       }

private void DoSort(int[] array)
        {
            MergeSorter ms = new MergeSorter(array);
            Func<int[]> del = new Func<int[]>(ms.sortArray);
            del.BeginInvoke(new AsyncCallback(SortCallback), null);
        }
        private void SortCallback(IAsyncResult ar)
        {
            AsyncResult result = (AsyncResult)ar;
            Func<int[]> del = (Func<int[]>)result.AsyncDelegate;
            try
            {
                int[] array = del.EndInvoke(ar);
                this.textBox1.Invoke(new MethodInvoker(
                    delegate()
                    {
                        string[] sArray = array.ToList().ConvertAll<string>(Convert.ToString).ToArray();
                        textBox1.Text = string.Join(", ", sArray);
                    }));
            }
            catch (Exception ex)
            {
                this.textBox1.Invoke(new MethodInvoker(delegate()
                {
                    textBox1.Text = "Error sorting array: " + Environment.NewLine + ex.Message;
                }));
            }
        }

    public class MergeSorter  {
    private int[] a;

    private int x;

private MergeSorter()
{
}
public MergeSorter(int[] array)
    :this()
{ this.a = array;
    this.x = array.Length; }
    public int[] sortArray()
    { q_sort(0, x - 1); return a; }
    private void q_sort(int left, int right)
    {
        int pivot, l_hold, r_hold;
        l_hold = left;
        r_hold = right;
        pivot = a[left];
        while
        (left < right)
        { while ((a[right] >= pivot) && (left < right))
        { right--; }
            if (left != right)
        { a[left] = a[right];
                left++; }
            while ((a[left] <= pivot) && (left < right))
            { left++; }
            if (left != right)
        { a[right] = a[left]; right--; }
        }
        a[left] = pivot;
        pivot = left;
        left = l_hold;
        right = r_hold;
        if (left < pivot)
        { q_sort(left, pivot - 1); }
        if (right > pivot)
        { q_sort(pivot + 1, right); }
    }
}