title: Asp.net POST parameter always null
body: <p>For passing an email address I'm using ajax with POST as type.</p>
  
  <pre><code>$.ajax({
      url: "api/Search/UserByEmail",
      type: "POST",
      data: JSON.stringify({ emailAddress: userEmail }),
      contentType: "application/json;charset=utf-8",
      dataType: "json",
      success: function (data) { ... }
  });
  </code></pre>
  
  <p>Controller:</p>
  
  <pre><code>[HttpPost]
  public IEnumerable&lt;Object&gt; UserByEmail([FromBody] string emailAddress) { ... }
  </code></pre>
  
  <p>That's what Fiddler says:</p>
  
  <pre><code>POST http://localhost:52498/api/Search/UserByEmail HTTP/1.1
  Accept: application/json, text/javascript, */*; q=0.01
  Content-Type: application/json;charset=utf-8
  X-Requested-With: XMLHttpRequest
  Referer: http://localhost:52498/#
  Accept-Language: de-DE
  Accept-Encoding: gzip, deflate
  User-Agent: Mozilla/5.0 (compatible; MSIE 10.0; Windows NT 6.1; WOW64; Trident/6.0)
  Host: localhost:52498
  Content-Length: 35
  DNT: 1
  Connection: Keep-Alive
  Pragma: no-cache
  
  {"emailAddress":"mail@example.com"}
  </code></pre>
  
  <p>Why is the emailAddress parameter always null?</p>