将ObservableCollection写入json文件

Question

我正在编写一个WPF应用程序，我将数据保存在JSON文件中。 问题是我在我的对象中有一个ObservableCollection来序列化，每次我写这个文件时它都没有写ObservableCollection！（其他变量写的都是正确的）我检查了它的集合并且它不是null。

class VarGlob
{
    private int demandeCount;
    private int etatDemandeObj;
    private ObservableCollection<Chapitre> dataContextObj;
    private static ObservableCollection<Chapitre> dataContext;
    private static int numBonDeCom;

    public int DemandeCount { get => demandeCount; set => demandeCount = value; }
    public int EtatDemandeObj { get => etatDemandeObj; set => etatDemandeObj = value; }
    public static ObservableCollection<Chapitre> DataContext { get => dataContext; set => dataContext = value; }
    internal ObservableCollection<Chapitre> DataContextObj { get => dataContextObj; set => dataContextObj = value; }

    public VarGlob()
    {
        DemandeCount = Demande.DemandeCount;
        EtatDemandeObj = Demande.EtatDemande;
        DataContextObj = DataContext;
    }
    public static void initVarGlob()
    {
        using (StreamReader file = File.OpenText(@"./VarGlob.json"))
        {
            JsonSerializer serializer = new JsonSerializer();
            VarGlob varGlob = (VarGlob) serializer.Deserialize(file, typeof(VarGlob));
            Demande.DemandeCount = varGlob.DemandeCount;
            Demande.EtatDemande = varGlob.EtatDemandeObj;
            if (varGlob.EtatDemandeObj == 0)
            {
                VarGlob.DataContext = Chapitre.GetChapitres("FirstDB");
            }else
                VarGlob.DataContext = varGlob.DataContextObj;

        }
    }
    public static void saveVarGlob()
    {
        File.WriteAllText(@".\VarGlob.json", JsonConvert.SerializeObject(new VarGlob()));
    }

这是文件内容：

{"DemandeCount":0,"EtatDemandeObj":0}

编辑：我忘了提到当我将ObservableCollection单独写入另一个文件时，它的工作原理是代码：

File.WriteAllText(@"./MainDataContext"+ ".json", JsonConvert.SerializeObject(DataContext));

感谢您的帮助！