private void worker_DoWork(object sender, DoWorkEventArgs e)

{

List<ulong> numbers = new List<ulong>();

// Calculate the first 90 numbers

int max = 90;

for (int i = 0; i < max; i++)

    {

// Every Fibonacci number equals the sum of the previous two Fibonacci numbers

// Special cases:   F(0) = 0 and F(1) = 1

//                  F(x) is undefined where x < 0

ulong number = 0;

if (i == 0)

            number = 0;

else if (i == 1)

            number = 1;

else

            number = numbers[i - 1] + numbers[i - 2];

        numbers.Add(number);

// Slow down the task by 50 ms each interation

        System.Threading.Thread.Sleep(50);

// Report the progress; calculating with decimal point

this.progress.Value = (int)((i + 1f) / max);

if (i == 0) this.list.Items.Clear();

ListViewItem lvi;

lvi = this.list.Items.Add("F(" + i + ")");

lvi.SubItems.Add(number.ToString());

    }

}