Error in webgrid using mvc4 razor

Question

I used like this

 grid.Column("AssignmentName", "Assignment", format: @<text>@Html.ActionLink(item.AssignmentName, "Details", new { id = item.AssignmentID }, null)</text>),

But i get this error. how do i rectify it?

Compiler Error Message: CS1502: The best overloaded method match for 'System.Web.Helpers.WebGrid.Column(string, string, System.Func<dynamic,object>, string, bool)' has some invalid arguments