使對象支持自定義比較

public class Order:IComparer,IComparable
{
　///略..........
 #region IComparer Members

        public int Compare(object x, object y)
        {
            Order orderX = (Order)x;
            Order orderY = (Order)y;
            return string.Compare(orderX.OrderColumn, orderY.OrderColumn);
        }

        #endregion

        #region IComparable Members

        public int CompareTo(object obj)
        {
            Order order = (Order)obj;
            return string.Compare(this.OrderColumn, order.OrderColumn);
        }

        #endregion

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