将 POST 中的 json 发送到 Web API 服务时出错

我正在使用 Web API 创建一个 Web 服务，我实现了一个简单的类

public class ActivityResult
{
public String code;
public int indexValue;
public int primaryCodeReference;
}

然后在控制器中实现

[HttpPost]
public HttpResponseMessage Post(ActivityResult ar)
{
return new HttpResponseMessage(HttpStatusCode.OK);
}

但是当我在 POST 中调用 API 时，文件 json:

{"code":"XXX-542","indexValue":"3","primaryCodeReference":"7"}

我获得以下错误消息:

{
"Message": "The request entity's media type 'text/plain' is not supported for this resource.",
"ExceptionMessage": "No MediaTypeFormatter is available to read an object of type 'ActivityResult' from content with media type 'text/plain'.",
"ExceptionType": "System.Net.Http.UnsupportedMediaTypeException",
"StackTrace": "   in System.Net.Http.HttpContentExtensions.ReadAsAsync[T](HttpContent content, Type type, IEnumerable`1 formatters, IFormatterLogger formatterLogger, CancellationToken cancellationToken)\r\n   in System.Net.Http.HttpContentExtensions.ReadAsAsync(HttpContent content, Type type, IEnumerable`1 formatters, IFormatterLogger formatterLogger, CancellationToken cancellationToken)\r\n   in System.Web.Http.ModelBinding.FormatterParameterBinding.ReadContentAsync(HttpRequestMessage request, Type type, IEnumerable`1 formatters, IFormatterLogger formatterLogger, CancellationToken cancellationToken)"
}

我做错了什么？

136684

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最佳答案

In the HTTP request you need to set Content-Type to: Content-Type: application/json

So if you're using fiddler client add Content-Type: application/json to the request header

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another tip...where to add "content-type: application/json"...to the textbox field on the Composer/Parsed tab. There are 3 lines already filled in there, so I added this Content-type as the 4th line. That made the Post work.

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Please check if you are were passing method as POST instead as GET. if so you will get same error as a you posted above.

$http({
method: 'GET',

The request entity's media type 'text/plain' is not supported for this resource.

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I had all my settings covered in the accepted answer. The problem I had was that I was trying to update the Entity Framework entity type "Task" like:

public IHttpActionResult Post(Task task)

What worked for me was to create my own entity "DTOTask" like:

public IHttpActionResult Post(DTOTask task)

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You have to must add header property Content-Type:application/json

When you define any POST request method input parameter that should be annotated as [FromBody], e.g.:

[HttpPost]
public HttpResponseMessage Post([FromBody]ActivityResult ar)
{
return new HttpResponseMessage(HttpStatusCode.OK);
}

Any JSON input data must be raw data.

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It require to include Content-Type:application/json in web api request header section when not mention any content then by default it is Content-Type:text/plain passes to request.

Best way to test api on postman tool.