Getting 500 internal server error when passing Json to MVC controller
<p>I want to pass 2 list string json to my controller and compare the changes.</p>

<p>Here is my model</p>

<pre><code>public class PhongtreeView
{
    public Guid Id { get; set; }
    public Guid? ParentId { get; set; }
}
</code></pre>

<p>And my controller </p>

<pre><code>public ActionResult SaveChanges(IEnumerable&lt;PhongtreeView&gt; InitTree,IEnumerable&lt;PhongtreeView&gt; UpdatedTree)
    {
        //Compare changes
        return View();
    }
</code></pre>

<p>My Ajax code</p>

<pre><code>$("#SaveChanges").click(function () {
    getJson();

    $.ajax({
        url: '@Url.Action("SaveChanges", "Phong")',
        type: "POST",
        data: {
            JSonFirst: JSON.stringify(StartTreeJson),
            JSonFinal: JSON.stringify(UpdatedTreeJson)
        },
        datatype: "json",
        contentType: "application/json",
        success: function (data) {
            if (!data.error) {
                alertify.success(" Success");
                //window.location.reload();

            }
            else {
                alertify.error(data.message);
            }
        }
    });   
</code></pre>

<p>But i always get the 500 internal error.If i remove the <strong>contentType: "application/json"</strong> it can run but it only pass null value to controller. Can someone tell me what's wrong ? Thank in advance.</p>