bazar.Accrual.CalculateIncomeSum C# (CSharp) Method

        protected void CalculateIncomeSum()
        {
            TreeIter iter;
            IncomeTotal = 0m;

            if(IncomeListStore.GetIterFirst(out iter))
            {
                IncomeTotal = Convert.ToDecimal(IncomeListStore.GetValue(iter,6));
                while (IncomeListStore.IterNext(ref iter))
                {
                    IncomeTotal += Convert.ToDecimal(IncomeListStore.GetValue(iter,6));
                }
            }
            labelIncomeSum.Text = string.Format("Сумма: {0:C} ", IncomeTotal);
            ShowStatus ();
        }