使用模型绑定和验证问题asp.net的Web API属性 [英] Problems with Model binding and validation attributes with asp.net Web API

问题描述

我写与的ASP.NET Web API上的Web API，并利用下面的视图模型。
我似乎有与数据绑定的问题时，有一个特定的属性两个验证属​​性（即[要求]和[StringLength（10）]）。

在发布来自客户端的JSON值到窗体的控制器动作：

// POST API /列表

公共无效后（[FromBody] TaskViewModel taskVM）

我注意以下事项：

• 如果我删除了多重属性之一，一切束缚OK;


• 如果我在多个属性离开时，客户端临危500内部服务器错误，永远达不到邮政法的主体。

任何想法，为什么出现这种情况？
干杯

 公共类TaskViewModel
{    //默认的构造函数
    公共TaskViewModel（）{}
    公共静态TaskViewModel MakeTaskViewModel（任务任务）
    {
        返回新TaskViewModel（任务）;
    }    //构造
    私人TaskViewModel（任务任务）
    {
        this.TaskId = task.TaskID;
        this.Description = task.Description;
        this.StartDate = task.StartDate;
        this.Status = task.Status;
        this.ListID = task.ListID;
    }    公众的Guid TASKID {搞定;组; }    [需要]
    [StringLength（10）]
    公共字符串描述{搞定;组; }    [需要]
    [数据类型（DataType.DateTime）
    公共System.DateTime的起始日期{搞定;组; }    [需要]
    公共字符串状态{搞定;组; }    公众的System.Guid ListID {搞定;组; }
}
 

解决方案

您需要检查的是在500内部服务器内部

• 请确保您打开 customerror 关闭在你的web.config


• 如果您selfhost web.API你需要设置 GlobalConfiguration.Configuration.IncludeErrorDetailPolicy = IncludeErrorDetailPolicy.Always;


• 使用浏览器的开发控制台的网络选项卡（IE，Chrome浏览器就可以得到与F12控制台），或者如果您使用的是Firefox，然后使用萤火或THRID第三方工具一样的提琴手。

这时你可以看到什么地方出了错在服务器上，并进一步去解决你的问题。

在你的情况，这是在响应：

  

消息：发生错误，ExceptionMessage：物业
  上键入'起始日期'MvcApplication3.Controllers.TaskViewModel'是
  无效。 值类型属性标记为[必填]也必须是
  标有[数据成员（IsRequired = TRUE）被确认为
  要求。考虑归因声明类型[DataContract]
  而财产
  [数据成员（IsRequired = TRUE）]，ExceptionType：System.InvalidOperationException

所以你的问题不在于你有两个属性，但已与标记你的属性[必需] 来解决这个异常会告诉你该怎么做。

您需要添加 [数据成员（IsRequired = TRUE）] 您需要的属性所在的属性类型是值类型（例如int，DATATIME等）：

因此​​，改变你的 TaskViewModel 来：

[DataContract]
公共类TaskViewModel
{    //默认的构造函数
    公共TaskViewModel（）{}    [数据成员]
    公众的Guid TASKID {搞定;组; }    [需要]
    [数据成员]
    [StringLength（10）]
    公共字符串描述{搞定;组; }    [需要]
    [数据成员（IsRequired =真）]
    [数据类型（DataType.DateTime）
    公共System.DateTime的起始日期{搞定;组; }    [需要]
    [数据成员]
    公共字符串状态{搞定;组; }    [数据成员]
    公众的System.Guid ListID {搞定;组; }
}


一些旁注：

• 您需要引用System.Runtime.Serialization DLL以使用 DataMemberAttribute


• 您需要标记与类[DataContract] 键，您需要使用 [数据成员] 不只是所需​​的项目。



I am writing a Web API with ASP.NET Web API, and make use of the following View Model. I seem to be having a problem with the data binding when there are two validation attributes on a particular property (i.e. [Required] and [StringLength(10)]).

When posting a JSON value from a client to a controller action of the form:

// POST api/list

public void Post([FromBody] TaskViewModel taskVM)

I observe the following:

• If I remove one of the multiple attributes everything is bound OK;
• If I leave in the multiple attributes, the client recieves a 500 internal server error and the body of the Post method is never reached.

Any ideas why this happens? Cheers

public class TaskViewModel
{

    //Default Constructor
    public TaskViewModel() { }


    public static TaskViewModel MakeTaskViewModel(Task task) 
    {
        return new TaskViewModel(task);
    }

    //Constructor
    private TaskViewModel(Task task)
    {
        this.TaskId = task.TaskID;
        this.Description = task.Description;
        this.StartDate = task.StartDate;
        this.Status = task.Status;
        this.ListID = task.ListID;
    }

    public Guid TaskId { get; set; }

    [Required]
    [StringLength(10)]
    public string Description { get; set; }

    [Required]
    [DataType(DataType.DateTime)]
    public System.DateTime StartDate { get; set; }

    [Required]
    public string Status { get; set; }        

    public System.Guid ListID { get; set; }       
}

解决方案

You need to inspect what is inside in the 500 internal server

• make sure that you turn customerror off in your web.config
• If you selfhost web.API you need to set GlobalConfiguration.Configuration.IncludeErrorDetailPolicy = IncludeErrorDetailPolicy.Always;
• use your browser development console's network tab (in IE, Chrome you can get the console with F12) or if you are using FireFox then use FireBug or a thrid party tool like Fiddler.

Then you can see what went wrong on the server and go further to solve your problem.

In your case this is in the response:

"Message":"An error has occurred.","ExceptionMessage":"Property 'StartDate' on type 'MvcApplication3.Controllers.TaskViewModel' 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"

So your problem is not that you have two attributes but that you've marked your properties with [Required] to solve this the exception tells you what to do.

You need to add [DataMember(IsRequired=true)] to your required properties where the property type is a value type (e.g int, datatime, etc.):

So change your TaskViewModel to:

[DataContract]
public class TaskViewModel
{

    //Default Constructor
    public TaskViewModel() { }

    [DataMember]
    public Guid TaskId { get; set; }

    [Required]
    [DataMember]
    [StringLength(10)]
    public string Description { get; set; }

    [Required]
    [DataMember(IsRequired = true)]
    [DataType(DataType.DateTime)]
    public System.DateTime StartDate { get; set; }

    [Required]
    [DataMember]
    public string Status { get; set; }

    [DataMember]
    public System.Guid ListID { get; set; }
}

Some side notes:

• You need to reference the System.Runtime.Serialization dll in order to use the DataMemberAttribute
• You need to mark your class with [DataContract] and you need to mark all of its properties with [DataMember] not just the required ones.

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