POST 字符串到 ASP.NET Web Api 应用程序 返回 null

我正在try 将一个字符串从客户端传输到ASP.NET MVC4应用程序.

但是我无法接收字符串，它可能是空的，或者找不到POST方法(404错误)

用于传输字符串的客户端代码(控制台应用程序):

HttpWebRequest request = (HttpWebRequest)WebRequest.Create("http://localhost:49032/api/test");
request.Credentials = new NetworkCredential("user", "pw");
request.Method = "POST";
string postData = "Short test...";
byte[] byteArray = Encoding.UTF8.GetBytes(postData);
request.ContentType = "application/x-www-form-urlencoded";
request.ContentLength = byteArray.Length;

Stream dataStream = request.GetRequestStream();
dataStream.Write(byteArray, 0, byteArray.Length);
dataStream.Close();

WebResponse response = request.GetResponse();
Console.WriteLine(((HttpWebResponse)response).StatusDescription);
dataStream = response.GetResponseStream();

StreamReader reader = new StreamReader(dataStream);
string responseFromServer = reader.ReadToEnd();
Console.WriteLine(responseFromServer);
reader.Close();
dataStream.Close();
response.Close();
Console.ReadLine();

ASP.NET Web Api控制器:

public class TestController : ApiController
{
    [Authorize]
    public String Post(byte[] value)
    {
        return value.Length.ToString();
    }
}

在这种情况下，我可以调用"Post"方法，但"value"是NULL. 如果我将方法签名更改为(字符串值)，那么它将永远不会被调用.

Even "without" the [Authorize] setting it has the same strange behavior. -> So it has nothing to do with the user authentication.

知道我做错了什么吗？