this 索引器的使用

    /// <summary>
    /// 泛型类(最多容纳100个T)
    /// </summary>
    /// <typeparam name="T"></typeparam>
    public class SampleCollection<T>
    {
        private T[] arr = new T[100];
        public T this[int index]
        {
            get
            {
                //检查索引范围
                return (index < 0 || index > 100) ? arr[0] : arr[index];
            }
            set
            {
                //检查索引范围
                if (index >= 0 && index <= 100)
                {
                    arr[index] = value;
                }
            }
        }
    }
    public class SampleCollection
    {
        private int[] arr = new int[100];
        public int this[int index]
        {
            get
            {
                //检查索引范围
                return (index < 0 || index > 100) ? arr[0] : arr[index];
            }
            set
            {
                //检查索引范围
                if (index >= 0 && index <= 100)
                {
                    arr[index] = value;
                }
            }
        }
 
    }

　　调用方式

 SampleCollection<string> Samples = new SampleCollection<string>();
            Samples[0] = "a";
            Samples[2] = "c";
            Samples[101] = "d";
            SampleCollection Samples2 = new SampleCollection();
            Samples2[0] = 2;
            Samples2[2] = 3;
            Console.ReadKey();