继承Exception 自定义异常信息:

案例如下：

    public class MyCustomException : System.Exception
    {
        //this：引用自身类的当前实例构造
        public MyCustomException(string message, int errorCode)
            : this(message, errorCode, 0, null) { }
        //base:用指定的内容去初始化父类相对应的构造函数中的变量信息
        public MyCustomException(string message, int errorCode, int level, DateTime? happenTime)
            : base(message)
        {
            ErrorCode = errorCode;
            Level = level;
            HappenTime = happenTime;
        }
        public int ErrorCode { get; set; }
        public int Level { get; set; }
        public DateTime? HappenTime { get; set; }

    }
//调用方式
            try
            {
                ThrowWithErrorCode(405);
            }
            catch (MyCustomException ex) when (ex.ErrorCode == 405)
            {
                Console.WriteLine($"Exception caught with filter {ex.Message} and {ex.ErrorCode}");
            }
            catch (MyCustomException ex)
            {
                Console.WriteLine($"Exception caught {ex.Message} and {ex.ErrorCode}");
            }
            string input = Console.ReadLine();