diff --git a/src/Banquale/Banquale/App.xaml.cs b/src/Banquale/Banquale/App.xaml.cs
index 011c988..5aee24c 100644
--- a/src/Banquale/Banquale/App.xaml.cs
+++ b/src/Banquale/Banquale/App.xaml.cs
@@ -7,7 +7,7 @@ namespace Banquale;
 public partial class App : Application
 {
 
-	public Manager MyManager { get; private set; } = new Manager(new Stub.Stub() /*DataContractPersistance.DataContractPers()*/);
+	public Manager MyManager { get; private set; } = new Manager(new Stub.Stub() /*DataContractPersistance.DataContractPersXML()*/);
 
 	
 
@@ -15,7 +15,7 @@ public partial class App : Application
 	{
 
 		MyManager.DataLoad();
-		MyManager.Persistence = new DataContractPersistance.DataContractPers();
+		MyManager.Persistence = new DataContractPersistance.DataContractPersXML();
         MyManager.DataSave();
 
 		InitializeComponent();
diff --git a/src/Banquale/Banquale/Banquale.csproj b/src/Banquale/Banquale/Banquale.csproj
index cc45e25..44d300a 100644
--- a/src/Banquale/Banquale/Banquale.csproj
+++ b/src/Banquale/Banquale/Banquale.csproj
@@ -70,7 +70,6 @@
 	</ItemGroup>
 	<ItemGroup>
 	  <Folder Include="Stub\" />
-	  <Folder Include="DataContractPersistance\" />
 	  <Folder Include="Views\Category\" />
 	</ItemGroup>
 	<ItemGroup>
diff --git a/src/Banquale/Banquale/DataContractPersistance/DataContractPersJSON.cs b/src/Banquale/Banquale/DataContractPersistance/DataContractPersJSON.cs
new file mode 100644
index 0000000..85df3fb
--- /dev/null
+++ b/src/Banquale/Banquale/DataContractPersistance/DataContractPersJSON.cs
@@ -0,0 +1,57 @@
+using Model;
+using System;
+using System.Collections.Generic;
+using System.Diagnostics;
+using System.Linq;
+using System.Runtime.Serialization.Json;
+using System.Text;
+using System.Threading.Tasks;
+
+
+
+namespace Banquale.DataContractPersistance
+{
+    public class DataContractPersJSON : IPersistenceManager
+    {
+
+        public string FilePath { get; set; } = FileSystem.Current.AppDataDirectory;
+        public string FileName { get; set; } = "DataSave.json";
+
+
+        public (List<Customer>, Consultant) DataLoad()
+        {
+            DataContractJsonSerializer jsonSerializer = new DataContractJsonSerializer(typeof(DataToPersist));
+
+            DataToPersist data;
+
+            using (FileStream stream2 = File.OpenRead(Path.Combine(FilePath, FileName)))
+            {
+                data = jsonSerializer.ReadObject(stream2) as DataToPersist;
+            }
+
+            return (data.customer, data.consultant);
+
+        }
+
+        public void DataSave(List<Customer> cu, Consultant co)
+        {
+
+            DataToPersist data = new DataToPersist();
+            data.customer = cu;
+            data.consultant = co;
+
+            DataContractJsonSerializer jsonSerializer = new DataContractJsonSerializer(typeof(DataToPersist));
+            using (FileStream stream = File.Create(Path.Combine(FilePath, FileName)))
+            {
+                using (var writer = JsonReaderWriterFactory.CreateJsonWriter(
+                            stream,
+                            System.Text.Encoding.UTF8,
+                            false,
+                            true))//<- this boolean says that we sant indentation
+                {
+                    jsonSerializer.WriteObject(writer, data);
+                }
+            }
+        }
+    }
+}
diff --git a/src/Banquale/Banquale/DataContractPersistance/DataContractPers.cs b/src/Banquale/Banquale/DataContractPersistance/DataContractPersXML.cs
similarity index 92%
rename from src/Banquale/Banquale/DataContractPersistance/DataContractPers.cs
rename to src/Banquale/Banquale/DataContractPersistance/DataContractPersXML.cs
index 70485c2..893ee04 100644
--- a/src/Banquale/Banquale/DataContractPersistance/DataContractPers.cs
+++ b/src/Banquale/Banquale/DataContractPersistance/DataContractPersXML.cs
@@ -8,7 +8,7 @@ using System.Xml;
 
 namespace Banquale.DataContractPersistance
 {
-	public class DataContractPers : IPersistenceManager
+	public class DataContractPersXML : IPersistenceManager
 	{
         //public string FilePath { get; set; } = Environment.GetFolderPath(Environment.SpecialFolder.Personal) + "/datbase.xml";
 
@@ -51,7 +51,8 @@ namespace Banquale.DataContractPersistance
 
 		public void DataSave(List<Customer> cu, Consultant co)
 		{
-            var serializer = new DataContractSerializer(typeof(DataToPersist));
+            var serializer = new DataContractSerializer(typeof(DataToPersist), new DataContractSerializerSettings() { PreserveObjectReferences = true }); 
+            // La deuxième partie sert à faire des références, cela sert à ne pas duppliquer l'écriture de certains attributs
 
             if (!Directory.Exists(FilePath))
             {
diff --git a/src/Banquale/Banquale/Stub/Stub.cs b/src/Banquale/Banquale/Stub/Stub.cs
index a401216..3749c51 100644
--- a/src/Banquale/Banquale/Stub/Stub.cs
+++ b/src/Banquale/Banquale/Stub/Stub.cs
@@ -20,7 +20,7 @@ namespace Banquale.Stub
             Customer Customer2 = new Customer("Francis", "Begore", "Halo");
             Customer Customer3 = new Customer("Michel", "Boudout", "Hola");
 
-            Account Account1 = new Account(999, "Tatouille", "FR76 9161 9581 6296 8415 2361 004");
+            Account Account1 = new Account(999, "Tatouille", "FR7691619581629684152361004");
             Account Account2 = new Account(9510, "Despoints", "FR7647858569691441525263003");
             Account Account3 = new Account(3519, "Perotte", "FR7663522541416969585847002");
 
diff --git a/src/Banquale/Banquale/Views/BalancePage.xaml b/src/Banquale/Banquale/Views/BalancePage.xaml
index 9915d12..0ef8203 100644
--- a/src/Banquale/Banquale/Views/BalancePage.xaml
+++ b/src/Banquale/Banquale/Views/BalancePage.xaml
@@ -69,12 +69,13 @@
             Grid.Row="1"
             HeightRequest="1"/>
 
-        <Label Text="{Binding TransactionsList.Id}"
+        <Label Text="{Binding TransactionsList[0].Id}"
                x:Name="idLabel" />
 
         <ListView ItemsSource="{Binding TransactionsList}"
                   Grid.Row="2"
                   SelectionMode="None">
+            <!--ItemSelected="Transactions_Clicked"-->
 
             <ListView.ItemTemplate>
 
diff --git a/src/Banquale/Banquale/Views/BalancePage.xaml.cs b/src/Banquale/Banquale/Views/BalancePage.xaml.cs
index a041029..33a525b 100644
--- a/src/Banquale/Banquale/Views/BalancePage.xaml.cs
+++ b/src/Banquale/Banquale/Views/BalancePage.xaml.cs
@@ -33,7 +33,7 @@ public partial class BalancePage : ContentPage
 
         if (string.IsNullOrWhiteSpace(idLabel.Text))
         {
-            await DisplayAlert("Erreur", "aucune transaction présente", "OK");
+            await DisplayAlert("Erreur", "Aucune transaction présente", "OK");
             return;
         }
 
diff --git a/src/Banquale/Model/Account.cs b/src/Banquale/Model/Account.cs
index 09372d3..400ccde 100644
--- a/src/Banquale/Model/Account.cs
+++ b/src/Banquale/Model/Account.cs
@@ -16,12 +16,12 @@ namespace Model
     /// Représente un compte bancaire.
     /// </summary>
     [DataContract]
-    public class Account : INotifyPropertyChanged, IEquatable<Account>
+    public class Account : INotifyPropertyChanged
     {
         /// <summary>
         /// Événement déclenché lorsqu'une propriété est modifiée.
         /// </summary>
-        public event PropertyChangedEventHandler PropertyChanged;
+        public event PropertyChangedEventHandler? PropertyChanged;
 
         /// <summary>
         /// Déclenche l'événement PropertyChanged pour une propriété donnée.
@@ -35,8 +35,8 @@ namespace Model
         /// <summary>
         /// Obtient ou définit le solde du compte.
         /// </summary>
-        [DataMember]
-        public Double Balance
+        [DataMember(Order = 3)]
+        public double Balance
         {
             get => balance;
             set
@@ -48,12 +48,12 @@ namespace Model
             }
         }
         [DataMember]
-        private Double balance;
+        private double balance;
 
         /// <summary>
         /// Obtient ou définit le nom du titulaire du compte.
         /// </summary>
-        [DataMember]
+        [DataMember(Order = 1)]
         public string Name
         {
             get => name;
@@ -71,7 +71,7 @@ namespace Model
         /// <summary>
         /// Obtient ou définit le numéro IBAN du compte.
         /// </summary>
-        [DataMember]
+        [DataMember(Order = 2)]
         public string IBAN
         {
             get => iban;
@@ -89,7 +89,7 @@ namespace Model
         /// <summary>
         /// Obtient une version masquée du numéro IBAN du compte.
         /// </summary>
-        [DataMember]
+        [DataMember(Order = 4)]
         public string IBANHide
         {
             get => ibanHide;
@@ -107,7 +107,7 @@ namespace Model
         /// <summary>
         /// Obtient ou définit la liste des transactions effectuées sur le compte.
         /// </summary>
-        [DataMember]
+        [DataMember(Order = 5)]
         public List<Transaction> TransactionsList { get; set; } = new List<Transaction>();
 
         /// <summary>
@@ -178,6 +178,7 @@ namespace Model
             return new string(res);
         }
 
+
         /// <summary>
         /// Vérifie si deux comptes sont égaux en comparant leur numéro IBAN.
         /// </summary>
diff --git a/src/Banquale/Model/Customer.cs b/src/Banquale/Model/Customer.cs
index f2f6184..5ad9c2f 100644
--- a/src/Banquale/Model/Customer.cs
+++ b/src/Banquale/Model/Customer.cs
@@ -13,7 +13,7 @@ namespace Model
     /// Représente un client.
     /// </summary>
     [DataContract]
-    public class Customer : Person
+    public class Customer : Person, IEquatable<Customer>//, IComparable<Customer>
     {
         /// <summary>
         /// Liste des comptes du client.
@@ -28,7 +28,18 @@ namespace Model
         /// <param name="firstName">Prénom du client.</param>
         /// <param name="password">Mot de passe du client.</param>
         public Customer(string name, string firstName, string password) : base(name, firstName, password)
-        { }
+        {}
 
+
+        public bool Equals(Customer? other)
+        {
+            if (other == null) return false;
+            else return other.Id.Equals(Id);
+        }
+
+        public override int GetHashCode()
+        {
+            return Id.GetHashCode();
+        }
     }
 }
diff --git a/src/Banquale/Model/Manager.cs b/src/Banquale/Model/Manager.cs
index 305498c..61d5862 100644
--- a/src/Banquale/Model/Manager.cs
+++ b/src/Banquale/Model/Manager.cs
@@ -15,11 +15,11 @@ namespace Model
     /// </summary>
     [DataContract]
     public class Manager : INotifyPropertyChanged
-    {
-        public event PropertyChangedEventHandler PropertyChanged;
+	{
+        public event PropertyChangedEventHandler? PropertyChanged;
 
-        void OnPropertyChanged([CallerMemberName] string propertyName = null)
-            => PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
+        void OnPropertyChanged([CallerMemberName] string? propertyName = null)
+				=> PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
 
         /// <summary>
         /// Liste des clients gérés par le gestionnaire.
diff --git a/src/Banquale/Model/Transaction.cs b/src/Banquale/Model/Transaction.cs
index c74c7f4..c68e10a 100644
--- a/src/Banquale/Model/Transaction.cs
+++ b/src/Banquale/Model/Transaction.cs
@@ -22,13 +22,13 @@ namespace Model
         /// <summary>
         /// Gets the unique identifier of the transaction.
         /// </summary>
-        [DataMember]
+        [DataMember(Order = 1)]
         public int Id { get; private set; }
 
         /// <summary>
         /// Gets or sets the type of the transaction (debit or credit).
         /// </summary>
-        [DataMember]
+        [DataMember(Order = 2)]
         public bool Type
         {
             get => type;
@@ -46,7 +46,7 @@ namespace Model
         /// <summary>
         /// Gets or sets the sum of the transaction.
         /// </summary>
-        [DataMember]
+        [DataMember(Order = 3)]
         public double Sum
         {
             get => sum;
@@ -64,7 +64,7 @@ namespace Model
         /// <summary>
         /// Gets or sets the account(s) involved in the transaction.
         /// </summary>
-        [DataMember]
+        [DataMember(Order = 4)]
         public Account InvolvedAccounts
         {
             get => involvedAccounts;
@@ -82,7 +82,7 @@ namespace Model
         /// <summary>
         /// Gets or sets the category of the transaction.
         /// </summary>
-        [DataMember]
+        [DataMember(Order = 5)]
         public string Category
         {
             get => category;
@@ -95,12 +95,12 @@ namespace Model
             }
         }
         [DataMember]
-        private string category;
+        private string? category;
 
         /// <summary>
         /// Gets or sets the date of the transaction.
         /// </summary>
-        [DataMember]
+        [DataMember(Order = 6)]
         public DateTime Date
         {
             get => date;
@@ -131,5 +131,11 @@ namespace Model
             InvolvedAccounts = involvedAccounts;
             Date = date;
         }
+
+        public void ChangeCategory(string newCateg)
+        {
+            Category = newCateg;
+        }
+
     }
 }