title: facebookclient.post() or .posttaskasync() with .net sdk returns invalid parameter when trying to post a link
body: <p>I've had this working in a previous version of my application and I tried using the old code, but I think the new sdk has something different going on.  I'm simply trying to post a link (that includes an image) to my wall and receiving an "Invalid Parameter" response.</p>
  
  <p>Here is the relevant code (I've also tried PostTaskAsync()...same result):</p>
  
  <pre><code>var client = new FacebookClient(accessToken);
              var postParams = new
              {
                  name = "the name",
                  caption = "the caption",
                  description = "the description",
                  link = "http://www.example.com/",
                  picture = "http://www.example.com/uploadedimages/myimage.jpg"
              };
              client.Post("me/feed", postParams);
  </code></pre>
  
  <p>I've tried substituting the object with a Dictionary with the same result.  I've tried substituting object with dynamic parameters = new ExpandoObject(); with the same result.</p>
  
  <p>If I post the object with just { message = "this is a test message" } it posts fine so I know that I have permissions to post on my wall.  Something just isn't jiving when I try to post the link with the image.  I also tried urlencoding the link and the image url and received a different error indicating that the "link/picture URL is not properly formatted".</p>
  
  <p>I stripped out all of the parameters thinking one of them was no longer supported, but still no dice.</p>
  
  <p>Here is the exact exception being thrown:</p>
  
  <blockquote>
    <p>Facebook.FacebookApiException: (FacebookApiException - #100) Invalid
    parameter    at Facebook.FacebookClient.ProcessResponse(HttpHelper
    httpHelper, String responseString, Type resultType, Boolean
    containsEtag, IList`1 batchEtags)    at
    Facebook.FacebookClient.Api(HttpMethod httpMethod, String path, Object
    parameters, Type resultType)    at Facebook.FacebookClient.Post(String
    path, Object parameters)</p>
  </blockquote>