System.Reflection 获取描述

我们需要获取类，属性，方法的描述。这个跟获取枚举的描述一样，需要我们通过反射来做。这还需要我们的利用System.ComponentModel：Description  的属性来完成。

新建一个类：使用的是：  System.ComponentModel：Description

 [Description("类的描述")]
    public class TestDes
    {
        [Description("id值")]
        public int Id { get; set; }

        [Description("名称")]
        public string Name { get; set; }

        /// <summary>
        /// 方法描述
        /// </summary>
        [Description("方法描述2")]
        public void Eat()
        {
            string d = "";
        }

        /// <summary>
        /// 得到方法重载
        /// </summary>
        [Description("方法描述3")]
        public void Eat(string aa)
        {
            string d = "";
        }
    }

三个扩展方法：

   public static class Exl
    {
        /// <summary>
        /// 获取类的描述
        /// </summary>
        /// <param name="t">类型</param>
        /// <returns></returns>
        public static string GetDescription(this Type t)
        {
            DescriptionAttribute[] attributes =
                   (DescriptionAttribute[])t.GetCustomAttributes(
                       typeof(DescriptionAttribute), false);
            return attributes.Length >  ? attributes[].Description : "";

        }

        /// <summary>
        /// 根据方法名获取描述
        /// </summary>
        /// <param name="method">方法名</param>
        /// <param name="t">类型</param>
        /// <param name="types">参数类型</param>
        /// <returns></returns>
        public static string GetDescriptionByMethod(this string method, Type t, params Type[] types)
        {

            System.Reflection.MethodInfo fi = t.GetMethod(method, types);
            if (fi != null)
            {
                DescriptionAttribute[] attributes =
                    (DescriptionAttribute[])fi.GetCustomAttributes(
                        typeof(DescriptionAttribute), false);
                return attributes.Length >  ? attributes[].Description : "";
            }
            return "";
        }

        /// <summary>
        /// 根据属性获取描述
        /// </summary>
        /// <param name="method">属性名称</param>
        /// <param name="t">类型</param>
        /// <returns></returns>
        public static string GetDescriptionByProperty(this string property, Type t)
        {
            System.Reflection.PropertyInfo fi = t.GetProperty(property);
            if (fi != null)
            {
                DescriptionAttribute[] attributes =
                    (DescriptionAttribute[])fi.GetCustomAttributes(
                        typeof(DescriptionAttribute), false);
                return attributes.Length >  ? attributes[].Description : "";
            }
            return "";
        }
    }

控制台：

 //获取类 需要命名空间+类名
            Type t = Type.GetType("ReflectionDemo.TestDes");
            //Attribute[] dd = (Attribute[])t.GetCustomAttributes(typeof(Attribute), false);
            string classDes = t.GetDescription();
            string proDes = "Name".GetDescriptionByProperty(t);
            string meDes = "Eat".GetDescriptionByMethod(t);
            string meDes2 = "Eat".GetDescriptionByMethod(t, new Type[] { typeof(string) });
            Console.WriteLine($"类：TestDes:{classDes}");
            Console.WriteLine($"属性：Name:{proDes}");
            Console.WriteLine($"方法：Eat:{meDes}");
            Console.WriteLine($"方法重载：Eat:{meDes2}");
            Console.ReadLine();

webapi中的异常过滤器：

 public class MyErrorFilter : ExceptionFilterAttribute
    {
        public override void OnException(HttpActionExecutedContext actionExecutedContext)
        {
            HttpActionContext context = actionExecutedContext.ActionContext;
            Type t = context.ControllerContext.Controller.GetType(); //得到控制器的类型
            string controllerDes = t.GetDescription(); //控制器的描述
            string controllerName = context.ActionDescriptor.ControllerDescriptor.ControllerName;//控制器的名称
            string actionName = context.ActionDescriptor.ActionName;//方法名
            string actionDes = actionName.GetDescriptionByMethod(t);//方法描述

            object obj = new
            {
                errcode = -,
                errmsg = actionExecutedContext.Exception
            };
            actionExecutedContext.Response = new HttpResponseMessage(HttpStatusCode.NotImplemented)
            {
                Content = new StringContent(JsonConvert.SerializeObject(obj), Encoding.UTF8, "application/json")
            };
            ////2.返回调用方具体的异常信息
            //if (actionExecutedContext.Exception is NotImplementedException)
            //{
            //    actionExecutedContext.Response = new HttpResponseMessage(HttpStatusCode.NotImplemented);
            //}
            //else if (actionExecutedContext.Exception is TimeoutException)
            //{
            //    actionExecutedContext.Response = new HttpResponseMessage(HttpStatusCode.RequestTimeout);
            //}
            ////.....这里可以根据项目需要返回到客户端特定的状态码。如果找不到相应的异常，统一返回服务端错误500
            //else
            //{
            //    actionExecutedContext.Response = new HttpResponseMessage(HttpStatusCode.InternalServerError);

            //}
            base.OnException(actionExecutedContext);
        }
    }