MVC Html.CheckBox

[shapper]

Hi,

I have the following on an Edit view to edit a IsPublished field:

<%= Html.CheckBox("IsPublished", "", "",
ViewData.Model.PostPaper.Post.IsPublished, new { @class = "CheckBox" })
%>

I get the error:

System.Web.Mvc.HtmlHelper' does not contain a definition for
'CheckBox' and the best extension method overload
'System.Web.Mvc.CheckBoxExtensions.CheckBox(System.Web.Mvc.HtmlHelper,
string, string, string, bool, object)' has some invalid arguments

What am I doing wrong?

Thanks,

Miguel