@Html.Label("Members", htmlAttributes: new { @class = "control-label required", @multiple = "multiple" })
 @Html.ListBoxFor(model => model.Members, (IEnumerable<SelectListItem>)ViewBag.Members, new { @class = "form-control", @multiple = "multiple" })
 @Html.ValidationMessageFor(model => model.Members, "", new { @class = "text-danger" })

[Required(ErrorMessage = "Please select a member")]
    public List<int> Members { get; set; }