Web Api 使用模型验证

    public class Person
    {
        public int Id { get; set; }

        [Required(ErrorMessage = "姓名不能为空啊啊啊!")]
        public string Name { get; set; }

        [Range(, , ErrorMessage = "年龄只能在18-25之间(包含18,25)")]
        public int Age { get; set; }
    }

    public class ValidateModelAttribute : ActionFilterAttribute
    {
        public override void OnActionExecuting(HttpActionContext actionContext)
        {
            //首先验证有否有入参,因为模型验证只能验证参数对不对,而无法验证有没有
            var flag = actionContext.ActionArguments.Values.First() == null;
            if (flag)
            {
                //返回错误消息方法一
                actionContext.Response = new HttpResponseMessage(HttpStatusCode.BadRequest)
                {
                    Content = new StringContent("入参为空")
                };
            }

            //如果有入参,再验证对不对
            else if (!actionContext.ModelState.IsValid)
            {
                var values = actionContext.ModelState.Values;

                // Errors 是个集合的原因是:一个属性有可能有多个验证规则
                var errorMessageList = values.SelectMany(ss => ss.Errors.Select(s => s.ErrorMessage));
                var errorMessage = string.Join(",", errorMessageList);

                //返回错误消息方法二
                actionContext.Response = actionContext.Request.CreateErrorResponse(HttpStatusCode.BadRequest, errorMessage);
            }
        }
    }

        [HttpPost]
        [ValidateModel]
        public void TestParam(Person person)
        {

        }

测试结果一:

            var url = "http://localhost:57895/api/test/TestParam";
            , name:  }
            $.ajax({
                url: url,
                type: "post",
                data: data
            });

测试结果二:

            var url = "http://localhost:57895/api/test/TestParam";
            , name:  }
            $.ajax({
                url: url,
                type: "post",
                //data: data
            });