Asp.net Web API 返回Json对象的两种方式

var content = new StringContent("{\"FileName\": \"" + fileName + "\"}");
HttpResponseMessage response = new HttpResponseMessage()
{
Content = content
};
response.Content.Headers.ContentType = new MediaTypeHeaderValue("application/json");

var fileNames = new Dictionary<string, string>();

fileNames.Add("FileName", fileName);
var content = new ObjectContent<Dictionary<string, string>>(fileNames, new JsonMediaTypeFormatter(), "application/json");
HttpResponseMessage response = Request.CreateResponse(HttpStatusCode.OK, content);