模型验证 - 为什么ModelState.IsValid总是返回true，即使不提供任何价值？ [英] Model validation - Why ModelState.IsValid always returns true even when no values are supplied?

问题描述

这是关于的WebAPI 和
以下是我的Model类。

This is regarding WEBAPI and the following is my Model class.

    public class Request
    {
        public int Id { get; set; }
        public string Name { get; set; }
        [Required]
        public Gender Gender { get; set; }
    }

和我的控制器功能（POST）

public class Values1Controller : ApiController
    {
        public IHttpActionResult Post([FromBody] Models.Request request)
        {
            if (!ModelState.IsValid)
            {
               return BadRequest();
            }
            var gender = request.Gender;
            var id = request.Id;
            var name = request.Name;
            // do some operations!
            return Ok();
        }
    }

和我与每个请求一起提交的XML。

And the xml that I submit along with each request.

<Request xmlns:i="http://www.w3.org/2001/XMLSchema-instance" 
                xmlns="http://schemas.datacontract.org/2004/07/webapi1.Models">
  <id>1</id>
  <name>testName</name>      
</Request>

在上面的XML post数据，我不为性别可言，它被标记为 [必需] 。

In the above XML post data, I do not supply a value for Gender at all, which are marked as [required].

但 ModelState.IsValid 返回true，即使在上面的XML是没有价值
为性别提供。

But the ModelState.IsValid returns true, even when in the above XML there is no value supplied for Gender.

如何从模型中的分配默认值一个枚举prevent的WebAPI？

How to prevent WebAPI from assigning default values to a enum in the model ?

任何想法，为什么？

推荐答案

我不知道为什么，如果你不提供性别你的模型是有效的，但你可以通过定义性别做出这个值没有默认值值可为空，如下所示：

I don't know why your model is valid if you don't supply gender, but you can make this value not have a default value by defining the Gender value as nullable, as follows:

public class Request
{
    public int id { get; set; }

    public string Name { get; set; }

    [Required]
    public Gender? Gender { get; set; }
}

另外，您可以指定性别的默认值，如下所示：

Alternatively you can specify a default value for gender, as follows:

public enum Gender
{
    Unknown = 0,
    Male,
    Female
} 

更新
我现在可以看到我们的结果之间的差异，再次使用<一个href=\"https://chrome.google.com/webstore/detail/postman-rest-client/fdmmgilgnpjigdojojpjoooidkmcomcm?hl=en\"相对=nofollow>邮差，如果​​我提交原始请求为XML：

Update I now can see the difference between our results, again using Postman, if I submit a raw request as xml:

标题：内容类型text / xml的

Header: Content-Type text/xml

<Request xmlns:i="http://www.w3.org/2001/XMLSchema-instance" 
         xmlns="http://schemas.datacontract.org/2004/07/webapi1.Models">
    <id>1</id>
    <Name>testName</Name>      
</Request>

我的模型是有效的，但如果我提交的X WWW的形式urlen codeD数据：

My model is valid, however if I submit x-www-form-urlencoded data:

标题：内容类型application / x-WWW的形式urlen codeD

Header: Content-Type application/x-www-form-urlencoded

id=1,Name=testname

然后我的模型是无效的，即使值类型有一个值，我的ModelState告诉我，性别属性是必需的。

Then my model is invalid, even though the value type has a value, my modelstate tells me that the Gender property is required.

为X-WWW的形式urlen codeD是查询字符串的一部分，那么我想这MVC是能够确定的价值不见了，但是当数据被提交为纯XML无法确定这一点。

As x-www-form-urlencoded is part of the query string then I guess that MVC is able to determine that the value was missing, but when the data is submitted as plain xml it can't determine this.

我建议，如果你想所需的属性在所有情况下工作，你让你的值类型可为空，如下所示：

I suggest that if you want the required attribute to work in all cases, you make your value types nullable as follows:

[Required]
public Gender? Gender { get; set; }

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