消除eliminate remove If-Else

测试消除If-Else代码如下：

#region 消除eliminate remove If-Else public static void TestRemoveIfElse() { Console.WriteLine($"TestRemoveIfElse"); TestIfElse testIfElse = new TestIfElse(); TestIfElse.TestOrder order = new TestIfElse.TestOrder { Id = 1, Name = "zhansan" }; var result = TestIfElse.RemoveIfElse(order, "json"); Console.WriteLine($"消除eliminate remove If-Else：{result}"); result = TestIfElse.RemoveIfElse1(order, "json"); Console.WriteLine($"消除eliminate remove If-Else：{result}"); result = TestIfElse.RemoveIfElse3(order, "json"); Console.WriteLine($"消除eliminate remove If-Else：{result}"); result = testIfElse.RemoveIfElse4(order, "json"); Console.WriteLine($"消除eliminate remove If-Else：{result}"); result = testIfElse.RemoveIfElse4(order, "plaintext"); Console.WriteLine($"消除eliminate remove If-Else：{result}"); }

    public class TestIfElse
    {
        /// <summary>
        /// 第一种方式，最常见的方式
        /// </summary>
        /// <param name="order"></param>
        /// <param name="formatType"></param>
        /// <returns></returns>
        public static string RemoveIfElse(TestOrder order, string formatType)
        {
            string result = string.Empty;
            if (formatType.Equals("json", StringComparison.OrdinalIgnoreCase))
            {
                result = JsonConvert.SerializeObject(order);
            }
            else if (formatType.Equals("plaintext", StringComparison.OrdinalIgnoreCase))
            {
                result = $"id={order.Id},name={order.Name}";
            }
            else
            {
                result = $"Unknown format";
            }
            return result;
        }

        /// <summary>
        /// 第二种方式，假设只有两种情况，也就是json和plaintext这两种格式
        /// </summary>
        /// <param name="order"></param>
        /// <param name="formatType"></param>
        /// <returns></returns>
        public static string RemoveIfElse1(TestOrder order, string formatType)
        {
            //先决条件
            if (string.IsNullOrWhiteSpace(formatType))
                return $"Unknown format";
            //if (formatType is null)
            //    return $"Unknown format";

            //处理逻辑
            return formatType == "json" ? JsonConvert.SerializeObject(order) : $"id={order.Id},name={order.Name}";
        }

        /// <summary>
        /// 第三种方式，使用字典处理key格式名称，value是Func<TestOrder, string>(对应的处理逻辑)
        /// </summary>
        /// <param name="order"></param>
        /// <param name="formatType"></param>
        /// <returns></returns>
        public static string RemoveIfElse3(TestOrder order, string formatType)
        {
            //先决条件
            if (string.IsNullOrWhiteSpace(formatType))
                return $"Unknown format";
            //字典应该是在其他位置预先设置好的，然后在这里使用，这里只为演示
            Dictionary<string, Func<TestOrder, string>> dict = new Dictionary<string, Func<TestOrder, string>>
            {
                ["json"] = a => JsonConvert.SerializeObject(a),
                ["plaintext"] = a => $"id={a.Id},name={a.Name}"
            };

            //处理逻辑
            return dict[formatType]?.Invoke(order);
        }

        #region 第四种方式使用反射和特性还有字典
        /// <summary>
        /// 第四种方式使用反射和特性还有字典
        /// </summary>
        /// <param name="order"></param>
        /// <param name="formatType">特性标记的名称(特性中定义的字段Name)</param>
        /// <returns></returns>
        public string RemoveIfElse4(TestOrder order, string formatType)
        {
            //先决条件
            if (string.IsNullOrWhiteSpace(formatType))
                return $"format is null";

            ////字典应该是在其他位置预先设置好的，然后在这里使用，这里只为演示
            var dict = GetType().Assembly
                .GetExportedTypes()
                .Where(t => t.GetInterfaces().Contains(typeof(IFormat123)))
                .ToDictionary(t => t.GetCustomAttribute<FlagFormatAttribute>().Name);

            if (dict[formatType] is null)
                return $"No valid format";

            //处理逻辑
            var format = Activator.CreateInstance(dict[formatType]) as IFormat123;
            return format.Format(order);
        }

        /// <summary>
        /// 格式化接口
        /// </summary>
        public interface IFormat123
        {
            /// <summary>
            /// 格式化处理方法
            /// </summary>
            /// <param name="order"></param>
            /// <returns></returns>
            string Format(TestOrder order);
        }

        /// <summary>
        /// json格式化
        /// </summary>
        [FlagFormat(Name = "json")]
        public class JsonFormat : IFormat123
        {
            public string Format(TestOrder order)
            {
                return JsonConvert.SerializeObject(order);
            }
        }

        /// <summary>
        /// plaintext格式化
        /// </summary>
        [FlagFormat(Name = "plaintext")]
        public class PlainTextFormat : IFormat123
        {
            public string Format(TestOrder order)
            {
                return $"id={order.Id},name={order.Name}";
            }
        }
        /// <summary>
        /// xml格式化
        /// </summary>
        [FlagFormat(Name = "xml")]
        public class XMLFormat : IFormat123
        {
            public string Format(TestOrder order)
            {
                return $"<id>{order.Id}></id>,<name>{order.Name}</name>";
            }
        }

        #endregion

        /// <summary>
        /// 测试类
        /// </summary>
        public class TestOrder
        {
            public int Id { get; set; }
            public string Name { get; set; }
        }

        /// <summary>
        /// 自定义特性，主要用于区分不同的对象
        /// </summary>
        [AttributeUsage(AttributeTargets.Class)]
        public class FlagFormatAttribute : Attribute
        {
            /// <summary>
            /// 名称
            /// </summary>
            public string Name { get; set; }
        }
    }
    #endregion

测试结果如下：

复制代码 public class Program { static void Main(string[] args) { #region 消除eliminate remove If-Else TestRemoveIfElse(); #endregion Console.Read(); } }