如何将json POST数据作为对象传递给Web API方法？ [英] How to pass json POST data to Web API method as an object?

问题描述

ASP.NET MVC4 Web API应用程序定义了保存客户的post方法。
客户在POST请求正文中以json格式传递。
post方法中的customer参数包含属性的空值。

ASP.NET MVC4 Web API application defines post method to save customer. Customer is passed in json format in POST request body. Customer parameter in post method contains null values for properties.

如何解决这个问题，以便将发布的数据作为客户对象传递？

How to fix this so that posted data will passed as customer object ?

如果可能的话Content-Type：application / x-www-form-urlencoded应该使用，因为我不知道如何在javascript方法中更改它发布表单。

If possible Content-Type: application/x-www-form-urlencoded should used since I dont know how to change it in javascript method which posts form.

控制器：

public class CustomersController : ApiController {

  public object Post([FromBody] Customer customer)
        {
            return Request.CreateResponse(HttpStatusCode.OK,
            new
            {
                customer = customer
            });
        }
    }
}

public class Customer
    {
        public string company_name { get; set; }
        public string contact_name { get; set; }
     }

请求：

POST http://localhost:52216/api/customers HTTP/1.1
Accept: application/json, text/javascript, */*; q=0.01
X-Requested-With: XMLHttpRequest
Content-Type: application/x-www-form-urlencoded; charset=UTF-8

{"contact_name":"sdfsd","company_name":"ssssd"}

推荐答案

编辑：31/10/2017

EDIT : 31/10/2017

相同代码/方法也适用于 Asp.Net Core 2.0 。主要区别在于，在asp.net核心中，web api控制器和Mvc控制器都合并到单个控制器模型中。所以你的返回类型可能是 IActionResult 或其中一个实现（例如： OkObjectResult ）

The same code/approach will work for Asp.Net Core 2.0 as well. The major difference is, In asp.net core, both web api controllers and Mvc controllers are merged together to single controller model. So your return type might be IActionResult or one of it's implementation (Ex :OkObjectResult)

使用

contentType:"application/json"

您需要使用 JSON.stringify 发送它时将其转换为JSON字符串的方法，

You need to use JSON.stringify method to convert it to JSON string when you send it,

模型绑定器将json数据绑定到您的类对象。

And the model binder will bind the json data to your class object.

以下代码可以正常工作（已测试）

The below code will work fine (tested)

$(function () {
    var customer = {contact_name :"Scott",company_name:"HP"};
    $.ajax({
        type: "POST",
        data :JSON.stringify(customer),
        url: "api/Customer",
        contentType: "application/json"
    });
});

结果

contentType 属性告诉服务器我们正在以JSON格式发送数据。由于我们发送了JSON数据结构，因此模型绑定将正确发生。

contentType property tells the server that we are sending the data in JSON format. Since we sent a JSON data structure,model binding will happen properly.

如果检查ajax请求的标头，则可以看到 Content-类型值设置为 application / json 。

If you inspect the ajax request's headers, you can see that the Content-Type value is set as application/json.

如果未指定contentType显式，它将使用默认内容类型 application / x-www-form-urlencoded;

If you do not specify contentType explicitly, It will use the default content type which is application/x-www-form-urlencoded;

编辑于2015年11月解决评论中提出的其他可能问题

假设你有一个复杂的视图模型类作为你的web api动作方法参数

Let's say you have a complex view model class as your web api action method parameter like this

public class CreateUserViewModel
{
   public int Id {set;get;}
   public string Name {set;get;}  
   public List<TagViewModel> Tags {set;get;}
}
public class TagViewModel
{
  public int Id {set;get;}
  public string Code {set;get;}
}

您的网络API终结点就像

and your web api end point is like

public class ProductController : Controller
{
    [HttpPost]
    public CreateUserViewMode Save([FromBody] CreateUserViewModel m)
    {
        // I am just returning the posted model as it is. 
        // You may do other stuff and return different response.
        // Ex : missileService.LaunchMissile(m);
        return m;
    }
}

在撰写本文时，ASP .NET MVC 6是最新的稳定版本，在MVC6中，Web api控制器和MVC控制器都继承自 Microsoft.AspNet.Mvc.Controller 基类。

要从客户端向方法发送数据，以下代码应该可以正常工作

To send data to the method from client side, the below code should work fine

//Build an object which matches the structure of our view model class
var model = {
    Name: "Shyju",
    Id: 123,
    Tags: [{ Id: 12, Code: "C" }, { Id: 33, Code: "Swift" }]
};

$.ajax({
    type: "POST",
    data: JSON.stringify(model),
    url: "../product/save",
    contentType: "application/json"
}).done(function(res) {       
    console.log('res', res);
    // Do something with the result :)
});

模型绑定适用于某些属性，但不是全部！为什么？

如果你没有用 [FromBody] 属性

[HttpPost]
public CreateUserViewModel Save(CreateUserViewModel m)
{
    return m;
}

并发送模型（原始javascript对象，不是JSON格式）而不指定contentType属性值

And send the model(raw javascript object, not in JSON format) without specifying the contentType property value

$.ajax({
    type: "POST",
    data: model,
    url: "../product/save"
}).done(function (res) {
     console.log('res', res);
});

模型绑定适用于模型上的平面属性，而不适用于类型复杂的属性/另一种类型。在我们的例子中， Id 和 Name 属性将正确绑定到参数 m ，但标签属性将是一个空列表。

Model binding will work for the flat properties on the model, not the properties where the type is complex/another type. In our case, Id and Name properties will be properly bound to the parameter m, But the Tags property will be an empty list.

如果出现同样的问题您使用的是简短版本 $ .posst ，它会在发送请求时使用默认的Content-Type。

The same problem will occur if you are using the short version, $.post which will use the default Content-Type when sending the request.

$.post("../product/save", model, function (res) {
    //res contains the markup returned by the partial view
    console.log('res', res);
});

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