C#开发中请多使用foreach

Posted 2021-06-20 老虎中的小白Gentle

什么是foreach

• forech就是传说中的增强for循环或者称作foreach循环

• forech对遍历字典或集合具备天然优势，效率高过for循环

foreach 操作数组

        public void TestFor1()
        {
            int[] ints = { 1, 2, 3 };
            foreach (int item in ints)
            {
                Console.WriteLine(item.ToString());
            }
        }

foreach 操作集合

        public void TestFor2()
        {
            List<int> intList = new List<int>() { 1, 2, 3, 4, 5 };
            foreach (int item in intList)
            {
                Console.WriteLine(item.ToString());
            }
        }

foreach 操作字典

       public void TestFor3()
        {

            Dictionary<string, string> dic = new Dictionary<string, string>()
            {
                { "A","aa"},
                { "B","bb"},
                { "C","cc"},
                { "D","dd" },
            };

            //KeyValuePair<string,string> 键值对的类型与字典中的一致
            foreach (KeyValuePair<string,string> item in dic)
            {
                string key = item.Key;
                string value = item.Value;

                Console.WriteLine("Key:{0}\\tValue:{1}", key, value);
            }