C# ASP.NET MVC 5序列化类型为'；的对象时检测到循环引用；数据项'；

我在ASP.NET MVC项目中遇到循环引用错误

这是模型

public partial class Item
{

    public Item()
    {
        this.Inventories = new HashSet<Inventory>();
        this.PurchasesDetails = new HashSet<PurchasesDetail>();
        this.SalesDetails = new HashSet<SalesDetail>();
    }

    public int Id { get; set; }
    public string Code { get; set; }
    public int CategoryID { get; set; }
    public string Name { get; set; }
    public int MeasurementID { get; set; }
    public int Quantity { get; set; }
    public decimal BuyPrice { get; set; }
    public decimal SalePrice { get; set; }
    public decimal CommisionRate { get; set; }
    public Nullable<System.DateTime> MftDate { get; set; }
    public Nullable<System.DateTime> ExpDate { get; set; }
    public Nullable<int> StockLimit { get; set; }
    public string Description { get; set; }
    public string UserID { get; set; }
    public virtual AspNetUser AspNetUser { get; set; }
    public virtual Category Category { get; set; }
    public virtual ICollection<Inventory> Inventories { get; set; }
    public virtual Measurement Measurement { get; set; }
    public virtual ICollection<PurchasesDetail> PurchasesDetails { get; set; }
    public virtual ICollection<SalesDetail> SalesDetails { get; set; }
}

---

我尝试了

db.Configuration.ProxyCreationEnabled=false但它不工作。非常感谢您的帮助。
在global.asax中，将以下代码用于全局Json序列化设置：

GlobalConfiguration.Configuration.Formatters.JsonFormatter.SerializerSettings.ReferenceLoopHandling = Newtonsoft.Json.ReferenceLoopHandling.Ignore;

尝试使用以下命令更改代码的以下部分：

string json = JsonConvert.SerializeObject(items, Formatting.None);
    return Json(new { data = json }, JsonRequestBehavior.AllowGet);

我也遇到了同样的问题，我试过这个

var plan_master = from s in db.Plan_Master select s;

        var plans = plan_master.Select(S => new
        {
            S.Plan_ID,
            S.Plan
        });

        return Json(new { data = plans }, JsonRequestBehavior.AllowGet);

我收到此错误“Newtonsoft.Json.JsonSerializationException:”检测到类型为“Data.Item”的自引用循环。路径“[0].AspNetUser.Items.”
var plan_master = from s in db.Plan_Master select s;

        var plans = plan_master.Select(S => new
        {
            S.Plan_ID,
            S.Plan
        });

        return Json(new { data = plans }, JsonRequestBehavior.AllowGet);