ASP. NET MVC 5 Web API about requested resource does not the support options issue

1. Build a Web API application with Visual Studio 2015. Remember that this is a Web API app.

2. Create a new Web API.

3, in C # Access, the code is as follows: [no problem, return correct]

varRequestjson =jsonconvert.serializeobject (args); Httpcontent httpcontent=Newstringcontent (Requestjson); HttpContent.Headers.ContentType=NewMediatypeheadervalue ("Application/json");varHttpClient =NewHttpClient ();varResponsejson = Httpclient.postasync ("http://webml01.dxqas.com/datacenter/api/affiliate/queryproduct", Httpcontent). Result.Content.ReadAsStringAsync (). Result;

But if you use jquery to invoke the Web API, it will appear:

  <Error><Message>The requested resource does not support http method ‘OPTIONS‘.</Message></Error>

  解决方法如下：
  
  1、编写一个 web api 的基类如 BaseApi.cs 继承自 ApiController 在BaseApi.cs中添加如下代码

 Public httpresponsemessage Options ()        {            returnnew httpresponsemessage {StatusCode = Httpstatuscode.ok};        }

2. Add the following configuration to the <system.webServer> node in Web. config

<customHeaders>
<add name= "Access-control-allow-origin" value= "*"/>
<add name= "Access-control-allow-methods" value= "GET, PUT, POST, DELETE, HEAD"/>
<add name= "Access-control-allow-headers" value= "Origin, X-requested-with, Content-type, Accept"/>
</customHeaders>

Complete the above two, then use jquery to call. No further error is given. However, when F12 looks at the request, it will find two requests generated.

ASP. NET MVC 5 Web API about requested resource does not support options issues