必需属性的DataAnnotation

Question

首先它有效,但今天它失败了!

这是我定义date属性的方法:

[Display(Name = "Date")]
[Required(ErrorMessage = "Date of Submission is required.")]        
[DisplayFormat(DataFormatString = "{0:d}", ApplyFormatInEditMode = true)]
[DataType(DataType.Date)]
public DateTime TripDate { get; set; }

它一直在工作.但今天,当我调用相同的ApiController动作时:

[HttpPost]
public HttpResponseMessage SaveNewReport(TripLeaderReportInputModel model)

萤火虫报道:

ExceptionMessage:

"Property 'TripDate' on type 'Whitewater.ViewModels.Report.TripLeaderReportInputModel' 
is invalid. Value-typed properties marked as [Required] must also be marked with
[DataMember(IsRequired=true)] to be recognized as required. Consider attributing the 
declaring type with [DataContract] and the property with [DataMember(IsRequired=true)]."

ExceptionType

"System.InvalidOperationException"

发生了什么？是不是那些[DataContract]对WCF？我正在使用REST WebAPI中MVC4!

有人可以帮忙吗？请？

---更新---

我发现了一些类似的链接.

MvC 4.0 RTM打破了我们,我们不知道如何修复RSS

---再次更新---

这是HTTP响应标头:

Cache-Control   no-cache
Connection  Close
Content-Length  1846
Content-Type    application/json; charset=utf-8
Date            Thu, 06 Sep 2012 17:48:15 GMT
Expires         -1
Pragma          no-cache
Server          ASP.NET Development Server/10.0.0.0
X-AspNet-Version    4.0.30319

请求标题:

Accept          */*
Accept-Encoding gzip, deflate
Accept-Language en-us,en;q=0.5
Cache-Control   no-cache
Connection          keep-alive
Content-Length  380
Content-Type    application/x-www-form-urlencoded; charset=UTF-8
Cookie          .ASPXAUTH=1FF35BD017B199BE629A2408B2A3DFCD4625F9E75D0C58BBD0D128D18FFDB8DA3CDCB484C80176A74C79BB001A20201C6FB9B566FEE09B1CF1D8EA128A67FCA6ABCE53BB7D80B634A407F9CE2BE436BDE3DCDC2C3E33AAA2B4670A0F04DAD13A57A7ABF600FA80C417B67C53BE3F4D0EACE5EB125BD832037E392D4ED4242CF6
DNT                 1
Host            localhost:39019
Pragma          no-cache
Referer         http://localhost:39019/Report/TripLeader
User-Agent          Mozilla/5.0 (Windows NT 6.1; WOW64; rv:15.0) Gecko/20100101 Firefox/15.0
X-Requested-With    XMLHttpRequest

---更新---

我找到了一个临时解决方案.见下面的答案.如果有人理解为什么它有效或有更好的解决方案,请发表您的答案.谢谢.

Answer 1

好的.虽然我还没有完全理解这件事.找到了解决方法.

在Global.asax:

GlobalConfiguration.Configuration.Services.RemoveAll(
    typeof(System.Web.Http.Validation.ModelValidatorProvider),
    v => v is InvalidModelValidatorProvider);

我在aspnetwebstack的问题跟踪器中找到了它.这是该页面的链接:

将[DataMember(IsRequired = true)]应用于具有值类型的必需属性的过度激进的验证

如果有人能告诉我们为什么会这样,请将您的见解发布为答案.谢谢.

Answer 2

我添加了一个ModelValidationFilterAttribute并使其工作:

public class ModelValidationFilterAttribute : ActionFilterAttribute
{
    public override void OnActionExecuting(HttpActionContext actionContext)
    {
        if (!actionContext.ModelState.IsValid)
        {
            // Return the validation errors in the response body.
            var errors = new Dictionary<string, IEnumerable<string>>();
            //string key;
            foreach (KeyValuePair<string, ModelState> keyValue in actionContext.ModelState)
            {
                //key = keyValue.Key.Substring(keyValue.Key.IndexOf('.') + 1);
                errors[keyValue.Key] = keyValue.Value.Errors.Select(e => e.ErrorMessage);
            }
            //var errors = actionContext.ModelState
            //    .Where(e => e.Value.Errors.Count > 0)
            //    .Select(e => new Error
            //    {
            //        Name = e.Key,
            //        Message = e.Value.Errors.First().ErrorMessage
            //    }).ToArray();

            actionContext.Response =
                actionContext.Request.CreateResponse(HttpStatusCode.BadRequest, errors);
        }
    }
}

您可以[ModelValidation]在操作上添加过滤器.或者将其添加到Global.asax.cs:

GlobalConfiguration.Configuration.Services.RemoveAll(
typeof(System.Web.Http.Validation.ModelValidatorProvider),
v => v is InvalidModelValidatorProvider);

这样,我继续使用原始数据注释.

参考

Answer 3

更新24-5-2013:已从 ASP.NET技术堆栈中删除InvalidModelValidatorProvider了对此错误消息的责任.该验证器证明引起的混淆比它要解决的更多.有关更多信息,请参阅以下链接:http://aspnetwebstack.codeplex.com/workitem/270

使用[DataContract]属性装饰类时,需要显式装饰要使用[DataMember]属性序列化的成员.

问题是DataContractSerializer不支持该[Required]属性.对于引用类型,我们可以在反序列化后检查该值是否为null.但是对于值类型,也没有办法为我们执行[Required]语义DataContractSerializer没有[DataMember(IsRequired=true)].

因此,如果未发送,则最终可能会标记为DateTimeas [Required]并期望模型验证错误DateTime,但您只需获取DateTime.MinValue值并且不会出现验证错误.