扩展方法

    static class TestExtend

    {

        /// <summary>

        /// 判断是否有重复添加

        /// </summary>

        /// <typeparam name="Tkey"></typeparam>

        /// <typeparam name="TValue"></typeparam>

        /// <param name="dict"></param>

        /// <param name="key"></param>

        /// <param name="value"></param>

        public static void AddSingle<Tkey, TValue>(this Dictionary<Tkey, TValue> dict, Tkey key, TValue value)

        {

            if (!dict.ContainsKey(key))

            {

                dict.Add(key, value);

            }

        }



        /// <summary>

        /// 批量添加

        /// </summary>

        /// <typeparam name="TKey"></typeparam>

        /// <typeparam name="TValue"></typeparam>

        /// <param name="dict"></param>

        /// <param name="keyValues"></param>

        public static void AddRange<TKey, TValue>(this Dictionary<TKey, TValue> dict, IEnumerable<KeyValuePair<TKey, TValue>> keyValues)

        {

            foreach (var item in keyValues)

            {

                if (!dict.ContainsKey(item.Key))

                    dict[item.Key] = item.Value;

            }

        }



        /// <summary>

        /// 替换为指定的字符

        /// </summary>

        /// <param name="str"></param>

        /// <param name="toChar"></param>

        /// <returns></returns>

        public static string ReplaceAToChar(this string str, string toChar)

        {

            return str.Replace("a", toChar);

        }



        /// <summary>

        /// 判断是否为数字

        /// </summary>

        /// <param name="str"></param>

        /// <returns></returns>

        public static bool isNumerice(this string str)

        {

            Regex r = new Regex(@"^\d+(\.)?\d*$");

            return (!r.IsMatch(str)) ? false : true;

        }

    }

        static void Main(string[] args)

        {

            var model = new Dictionary<string, string>();

            model.Add("001", "中国");

            model.AddSingle("002", "美国");//判断重复添加值



            var listModel = new Dictionary<string, string>();

            listModel.AddRange(model);//批量添加Key/Value值

            foreach (var item in listModel)

            {

                Console.WriteLine("Key:" + item.Key + "  Value:" + item.Value);

            }



            string test = "jacky";

            Console.WriteLine(test.ReplaceAToChar("@"));

            test = "12.88";

            Console.WriteLine(test.isNumerice());

        }

输出值：