Object reference not set to an instance of an object, parameter is null

Question

I am having issues with passing an argument from my view to my controller

I have this code fragment in my view:

<a class="btn-simple" onclick="submitDetails('Dashboard', 'Cancel', '<%=Model.Data.Id %>', $('form'));">save</a>

and this is from my controller:

[HttpPost]
public ActionResult Cancel(string id, FormCollection collection)
{
       var appt = Application.Session.GetObjectFromOid<Appointment>(new ObjectId(id));
}

I get an error saying that "id" is null, but when I test Model.Data.Id in the view, it is not null.

And this is my submitDetails function:

function submitDetails(controller, method, id, form) {
    form.ajaxSubmit({ target: '#itemdetails' });

}

What I am trying to accomplish is getting back to my controller from a button in the view, the "[HttpPost]" version of the method that originally called the view

Answer 1

Make sure that the form you are submitting contains a hidden field with the id or it is passed as query string parameter:

<% using (Html.BeginForm("Dashboard", "Cancel", new { id = Model.Data.Id })) { %>
    ...
<% } %>

or if you want to pass a dynamic url you could do the following:

<a class="btn-simple" onclick="submitDetails('<%= Url.Action("Dashboard", "Cancel", new { id = Model.Data.Id }) %>', $('form'));">save</a>

and then:

function submitDetails(url, form) {
    form.ajaxSubmit({ url: url, target: '#itemdetails' });
}

---

UPDATE:

And if you want to avoid the submitDetails javascript method and have your anchor be the submit button of the form:

<% using (Html.BeginForm("Dashboard", "Cancel", new { id = Model.Data.Id })) { %>
    ...

    <button class="btn-simple" type="submit">save</button>
<% } %>