Correction of DataContract Problem and Add better version of dataBinding

src/Banquale/Banquale/App.xaml.cs

@@ -16,7 +16,7 @@ public partial class App : Application
 
 		MyManager.DataLoad();
 		MyManager.Persistence = new DataContractPersistance.DataContractPers();
-        //MyManager.DataSave();
+        MyManager.DataSave();
 
 		InitializeComponent();
 

src/Banquale/Banquale/Model/Manager.cs

@@ -1,11 +1,18 @@
 using System;
+using System.ComponentModel;
+using System.Runtime.CompilerServices;
 using System.Runtime.Serialization;
 
 namespace Banquale.Model
 {
 	[DataContract]
-	public class Manager
+    public class Manager : INotifyPropertyChanged
 	{
+        public event PropertyChangedEventHandler PropertyChanged;
+
+        void OnPropertyChanged([CallerMemberName] string propertyName = null)
+				=> PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
+
         [DataMember]
 		public List<Customer> CustomersList { get; private set; } // devient un set
 
@@ -17,7 +24,10 @@ namespace Banquale.Model
 			get => selectedCustomer;
 			set
 			{
+				if (selectedCustomer == value)
+					return;
 				selectedCustomer = value;
+				OnPropertyChanged();
 			}
 		}
 
@@ -28,7 +38,10 @@ namespace Banquale.Model
 			get => selectedAccount;
 			set
 			{
+                if (selectedAccount == value)
+                    return;
                 selectedAccount = value;
+                OnPropertyChanged();
             }
 		}
 
@@ -39,12 +52,17 @@ namespace Banquale.Model
             get => selectedTransaction;
             set
             {
+                if (selectedTransaction == value)
+                    return;
                 selectedTransaction = value;
+                OnPropertyChanged();
             }
         }
 
         private Transactions selectedTransaction;
 
+        
+
         public IPersistenceManager Persistence { get; set; }
 
 		public Manager(IPersistenceManager persistence)

src/Banquale/Banquale/Model/Transactions.cs

@@ -3,7 +3,7 @@ using System.Runtime.Serialization;
 
 namespace Banquale.Model
 {
-    [DataContract]
+    [DataContract(IsReference = true)]
     public class Transactions : INotifyPropertyChanged
     {
 

src/Banquale/Banquale/Views/BalancePage.xaml.cs

@@ -18,6 +18,7 @@ public partial class BalancePage : ContentPage
     public async void Transaction_Clicked(System.Object sender, Microsoft.Maui.Controls.TappedEventArgs e)
     {
         Mgr.SelectedTransaction = Mgr.SelectedAccount.TransactionsList[0];
+        //Mgr.SelectedTransaction = Mgr.PropertyChanged;
         await Shell.Current.Navigation.PushAsync(new TransactionsPage());
     }
     public async void Balance_Clicked(object sender, EventArgs e)

src/Banquale/Banquale/Views/ConnectionPage.xaml.cs

@@ -27,6 +27,15 @@ public partial class ConnectionPage : ContentPage
             return;
         }
 
+
+        /*foreach(var Cu in Mgr.CustomersList)
+        {
+            if (Cu.Id == currentId)
+            {
+                Mgr.SelectedCustomer = Mgr.CustomersList[currentId+1];
+            }
+        }*/
+
         //if(int.Parse(currentId) in Mgr.CustomersList) // FONCTIONNE PAS
         //{
         //    Mgr.SelectedCustomer = Mgr.CustomersList[int.Parse(currentId)];