public JsonResult IndexJson(BootgridRequestData model)
{
    var contacts = (from x in db.ContactSet
                    select new
                    {
                        x.AccountId,
                        x.FirstName,
                        x.LastName,
                        x.FullName,
                        x.JobTitle,
                        x.ParentCustomerId,
                        x.EMailAddress1,
                        x.Telephone1,
                        x.MobilePhone,
                        x.Fax,
                        x.GenderCode,
                        x.BirthDate
                    }).ToList();

    // This tResult throws a Non-invocable member cannot be used like a method error.
    var tResult = BootgridResponseData<JsonResult>() {
        current = model.current,
        rowCount = model.rowCount,
        rows = contacts,
        total = contacts.Count
    };

    return Json(tResult, JsonRequestBehavior.AllowGet);
}

public class BootgridRequestData
{
    public int current { get; set; }
    public string rowCount { get; set; }
    public string searchPhrase { get; set; }
    public IEnumerable<SortData> sortItems { get; set; }
}

public class BootgridResponseData<T> where T : class
{
    public int current { get; set; } //? current page
    public int rowCount { get; set; } //? rows per page
    public IEnumerable<T> rows { get; set; } //? items
    public int total { get; set; } //? total rows for whole query
}

public class SortData
{
    public string Field { get; set; } //? Field Name
    public string Type { get; set; } //? ASC or DESC
}