The type arguments for method 'GridHelper.Grid<T>(HtmlHelper, IEnumerable<T>)' cannot be inferred from the usage. error

Question

I'm getting "The type arguments for method 'GridHelper.Grid(HtmlHelper, IEnumerable)' cannot be inferred from the usage. Try specifying the type arguments explicitly.'" error. How can I fix this?

<div class="row">
    <div class="col-xs-12">
        @(Html.Grid(Model)
            .Name((string)ViewBag.XName+" Visitor List")
            .PKColumn(p => p.ID)
            .Columns(c =>
            {
                c.Add(a => a.Name);
                c.Add(a => a.Surname);
                
            })
            .RowButtons(b =>
            {
                b.Add(GridButtonType.update);
            })

            .ToolbarButtons(b =>
            {
                b.Add(GridButtonType.insert).CssClass("btn btn-primary").Icon("fa-plus").Title("Add Visit").ActionUrl(Url.Action("AddVisit"));
                //b.Add(GridButtonType.insert).CssClass("btn btn-primary").Icon("fa-plus").Title("Visitor Register").ActionUrl(Url.Action("VisitorRegister"));

            })
            .UpdateURL(Url.Action("AddVisit"))
            .DeleteURL("Delete"))

    </div>
</div>