title: What does HttpResponseMessage return as Json
body: <p>I have a basic question about basics on Web Api. FYI, I have checked before but could not found what I was looking for.</p>
  
  <p>I have a piece of code as described below these lines. Just like any other Method in general terms my method called: Post, it has to return something,a JSON for example, How do I do that. 
  Specifically, what am I supposed to write after the word " return " in order to get the 3 fields( loginRequest.Username,loginRequest.Password,loginRequest.ContractItemId ) as Json.
  Coments: Do not worry about username,password and contractID are in comments, I do get their value in my LinQ. It's just the return whta I nened now, greetings to all who would like to throw some notes about this.</p>
  
  <pre><code>    [System.Web.Http.HttpPost]
      public HttpResponseMessage Post(LoginModel loginRequest)
      {
          //loginRequest.Username = "staw_60";
          //loginRequest.Password = "john31";
          //loginRequest.ContractItemId = 2443;
  
        try
          {
             Membership member =
                  (from m in db.Memberships
                   where
                       m.LoginID == loginRequest.Username 
                   &amp;&amp; m.Password == loginRequest.Password 
                   &amp;&amp; m.ContractItemID == loginRequest.ContractItemId
                   select m).SingleOrDefault();   
          }
         catch (Exception e)
         {
              throw new Exception(e.Message);
         }
  
        return ???;      
      }
  </code></pre>