diff --git a/WF-WebAdmin/WF-WebAdmin/Pages/DeleteUser.razor b/WF-WebAdmin/WF-WebAdmin/Pages/DeleteUser.razor
index 10ce548..14fb290 100644
--- a/WF-WebAdmin/WF-WebAdmin/Pages/DeleteUser.razor
+++ b/WF-WebAdmin/WF-WebAdmin/Pages/DeleteUser.razor
@@ -5,7 +5,7 @@
 
 <h3>@Localizer["TitleUser"]</h3>
 
-@if(users == null)
+@if(_users == null)
 {
     <p><strong>@Localizer["UserNobody"]</strong></p>
 }
@@ -13,10 +13,10 @@
 else
 {
     <DataGrid TItem="User"
-              Data="@users"
+              Data="@_users"
               PageSize="@MaxValue"
               ReadData="@OnReadData"
-              TotalItems="@totalItem"
+              TotalItems="@_totalItem"
               ShowPager
               Responsive>
 
@@ -29,7 +29,7 @@ else
 
     <p>@Localizer["UserHere"]</p>
 
-    @foreach (var user in users)
+    @foreach (var user in _users)
     {
         <div class="userDiv" id="@user.Id">
             <img class="imgProfil" src="@user.Image" />
@@ -74,7 +74,7 @@ else
         </div>
 
     <!-- Fenêtre de confirmation de suppression -->
-    @if (showPopupDelete)
+    @if (_showPopupDelete)
     {
         <div class="divPopup">
             <div class="contentPopup">
@@ -84,17 +84,17 @@ else
             </div>
         </div>
     }
-    @if (showModifyPopup)
+    @if (_showModifyPopup)
     {
         <div class="divPopup">
             <div class="contentPopup">
                 <p>Modifier les informations de l'utilisateur :</p>
                 <label>Nom d'utilisateur:</label>
-                <input type="text" @bind="selectedUser.Name"/>
+                <input type="text" @bind="_selectedUser.Name"/>
                 <label>Email:</label>
-                <input type="email" @bind="selectedUser.Email" />
+                <input type="email" @bind="_selectedUser.Email" />
                 <label>Image:</label>
-                <input type="text" @bind="selectedUser.Image" />
+                <input type="text" @bind="_selectedUser.Image" />
                 <button @onclick="ModifyUser">Sauvegarder</button>
                 <button @onclick="ClosePopup">Annuler</button>
             </div>
@@ -103,7 +103,7 @@ else
 }
 
     <!-- Fenêtre de confirmation d'ajout admin-->
-    @if (showPopupAdmin)
+    @if (_showPopupAdmin)
     {
         <div class="divPopup">
             <div class="contentPopup">
diff --git a/WF-WebAdmin/WF-WebAdmin/Pages/DeleteUser.razor.cs b/WF-WebAdmin/WF-WebAdmin/Pages/DeleteUser.razor.cs
index a508c85..05f90be 100644
--- a/WF-WebAdmin/WF-WebAdmin/Pages/DeleteUser.razor.cs
+++ b/WF-WebAdmin/WF-WebAdmin/Pages/DeleteUser.razor.cs
@@ -14,30 +14,30 @@ namespace WF_WebAdmin.Pages
         [Inject]
         public ILogger<DeleteUser>? Logger { get; set; }
 
-        private List<User> users;
+        private List<User>? _users;
 
-        private bool showModifyPopup = false;
-        private User userToDelete = null;
-        private User selectedUser;
-        private bool showPopupDelete = false;
-        private bool showPopupAdmin = false;
-        private User userToAdmin = null;
-        private int MaxValue = 5;
-        private int totalItem;
-        private int page = 1;
+        private bool _showModifyPopup = false;
+        private User? _userToDelete = null;
+        private User? _selectedUser;
+        private bool _showPopupDelete = false;
+        private bool _showPopupAdmin = false;
+        private User? _userToAdmin = null;
+        private const int MaxValue = 5;
+        private int _totalItem;
+        private int _page = 1;
 
 
         [Inject]
-        public HttpClient Http { get; set; }
+        public HttpClient? Http { get; set; }
 
         [Inject]
-        public NavigationManager NavigationManager { get; set; }
+        public NavigationManager? NavigationManager { get; set; }
 
         [Inject]
-        private IUserService userService { get; set; }
+        private IUserService? UserService { get; set; }
 
         [Inject]
-        public IStringLocalizer<DeleteUser> Localizer { get; set; }
+        public IStringLocalizer<DeleteUser>? Localizer { get; set; }
 
 
 
@@ -50,7 +50,7 @@ namespace WF_WebAdmin.Pages
         {
             // Retrieve a list of users using the user service. The number of users and page number are specified.
             // MaxValue determines how many users to retrieve, and '1' refers to the first page of results.
-            users = await userService.getSomeUser(MaxValue, 1);
+            _users = await UserService.getSomeUser(MaxValue, 1);
         }
 
 
@@ -71,14 +71,14 @@ namespace WF_WebAdmin.Pages
             }
 
             // Fetch a page of users from the user service using the page size and page number provided by the event arguments.
-            var response = await userService.getSomeUser(e.PageSize, e.Page);
+            var response = await UserService.getSomeUser(e.PageSize, e.Page);
 
             // If the operation is not cancelled, update the total number of users and the list of users.
             if (!e.CancellationToken.IsCancellationRequested)
             {
-                totalItem = await userService.getNbUser(); // Get the total number of users
-                users = new List<User>(response.ToArray()); // Store the retrieved users in the users list
-                page = e.Page; // Update the current page number
+                _totalItem = await UserService.getNbUser(); // Get the total number of users
+                _users = new List<User>(response.ToArray()); // Store the retrieved users in the users list
+                _page = e.Page; // Update the current page number
             }
         }
 
@@ -90,11 +90,11 @@ namespace WF_WebAdmin.Pages
         /// and it sets the user to be deleted and shows the confirmation popup.
         /// </summary>
         /// <param name="user">The user to be deleted, which is passed to the method for confirmation.</param>
-        private void ShowConfirmation(User user)
+        private void ShowConfirmation(User? user)
         {
             // Set the user to be deleted and show the confirmation popup.
-            userToDelete = user; // Store the user to be deleted in a variable
-            showPopupDelete = true; // Display the confirmation popup
+            _userToDelete = user; // Store the user to be deleted in a variable
+            _showPopupDelete = true; // Display the confirmation popup
         }
 
 
@@ -104,11 +104,11 @@ namespace WF_WebAdmin.Pages
         /// and it sets the selected user and shows the modification confirmation popup.
         /// </summary>
         /// <param name="user">The user whose information is to be modified, passed to the method for confirmation.</param>
-        private void ShowModifyConfirmation(User user)
+        private void ShowModifyConfirmation(User? user)
         {
             // Set the selected user and show the modification confirmation popup.
-            selectedUser = user; // Store the user to be modified
-            showModifyPopup = true; // Display the confirmation popup for modification
+            _selectedUser = user; // Store the user to be modified
+            _showModifyPopup = true; // Display the confirmation popup for modification
         }
 
 
@@ -121,20 +121,20 @@ namespace WF_WebAdmin.Pages
         private async Task RemoveUser()
         {
             // Check if there is a user to delete
-            if (userToDelete != null)
+            if (_userToDelete != null)
             {
                 // Remove the selected user from the system using the user service
-                LoggerSaveStub.Log(Logger, LogLevel.Information, $"Delete user {userToDelete.Name}");
-                await userService.removeUser(userToDelete);
+                LoggerSaveStub.Log(Logger, LogLevel.Information, $"Delete user {_userToDelete.Name}");
+                await UserService.removeUser(_userToDelete);
 
                 // Close the confirmation popup after the deletion
                 ClosePopup();
 
                 // Refresh the list of users by fetching the updated data from the user service
-                var response = await userService.getSomeUser(MaxValue, page);
+                var response = await UserService.getSomeUser(MaxValue, _page);
 
                 // Update the users list with the latest data
-                users = new List<User>(response.ToArray());
+                _users = new List<User>(response.ToArray());
             }
         }
 
@@ -147,8 +147,8 @@ namespace WF_WebAdmin.Pages
         private async Task ModifyUser()
         {
             // Update the selected user's information using the user service
-            LoggerSaveStub.Log(Logger, LogLevel.Information, $"Modification of user {selectedUser.Name}");
-            await userService.updateUser(selectedUser);
+            LoggerSaveStub.Log(Logger, LogLevel.Information, $"Modification of user {_selectedUser.Name}");
+            await UserService.updateUser(_selectedUser);
 
             // Close the modification popup after the update is complete
             ClosePopup();
@@ -163,9 +163,9 @@ namespace WF_WebAdmin.Pages
         private void ClosePopup()
         {
             // Set all popup visibility flags to false to hide the popups
-            showModifyPopup = false;  // Close the modify confirmation popup
-            showPopupDelete = false;  // Close any additional delete popups
-            showPopupAdmin = false;   // Close the admin-related popup (if any)
+            _showModifyPopup = false;  // Close the modify confirmation popup
+            _showPopupDelete = false;  // Close any additional delete popups
+            _showPopupAdmin = false;   // Close the admin-related popup (if any)
         }
 
 
@@ -176,11 +176,11 @@ namespace WF_WebAdmin.Pages
         /// It sets the selected user to be promoted and shows the confirmation popup for admin promotion.
         /// </summary>
         /// <param name="user">The user to be promoted to admin, passed to the method for confirmation.</param>
-        private void ShowConfirmationAdmin(User user)
+        private void ShowConfirmationAdmin(User? user)
         {
             // Set the user to be promoted to admin and show the confirmation popup.
-            userToAdmin = user; // Store the user to be promoted
-            showPopupAdmin = true; // Display the confirmation popup for admin promotion
+            _userToAdmin = user; // Store the user to be promoted
+            _showPopupAdmin = true; // Display the confirmation popup for admin promotion
         }
 
 
@@ -194,20 +194,20 @@ namespace WF_WebAdmin.Pages
         private async Task setAdmin()
         {
             // Check if the user is not already an admin
-            if (!userToAdmin.IsAdmin)
+            if (!_userToAdmin.IsAdmin)
             {
                 // Promote the user to admin
-                LoggerSaveStub.Log(Logger, LogLevel.Information, $"User {userToAdmin.Name} is now administrator");
-                userToAdmin.IsAdmin = true;
-                await userService.updateUser(userToAdmin); // Update the user status in the service
+                LoggerSaveStub.Log(Logger, LogLevel.Information, $"User {_userToAdmin.Name} is now administrator");
+                _userToAdmin.IsAdmin = true;
+                await UserService.updateUser(_userToAdmin); // Update the user status in the service
                 ClosePopup(); // Close the confirmation popup
             }
             else
             {
                 // Demote the user from admin to normal user
-                LoggerSaveStub.Log(Logger, LogLevel.Information, $"User {userToAdmin.Name} is no longer an administator");
-                userToAdmin.IsAdmin = false;
-                await userService.updateUser(userToAdmin); // Update the user status in the service
+                LoggerSaveStub.Log(Logger, LogLevel.Information, $"User {_userToAdmin.Name} is no longer an administator");
+                _userToAdmin.IsAdmin = false;
+                await UserService.updateUser(_userToAdmin); // Update the user status in the service
                 ClosePopup(); // Close the confirmation popup
             }
         }
diff --git a/WF-WebAdmin/WF-WebAdmin/Service/IUserService.cs b/WF-WebAdmin/WF-WebAdmin/Service/IUserService.cs
index 7357e21..149f163 100644
--- a/WF-WebAdmin/WF-WebAdmin/Service/IUserService.cs
+++ b/WF-WebAdmin/WF-WebAdmin/Service/IUserService.cs
@@ -6,15 +6,15 @@ namespace WF_WebAdmin.Service
     {
         public Task removeUser(User user);
 
-        public Task updateRole(User user);
+        public Task updateRole(User? user);
 
-        public Task downgradeRole(User user);
+        public Task downgradeRole(User? user);
 
-        public Task updateUser(User user);
+        public Task updateUser(User? user);
 
         public Task<List<User>> getAllUser();
 
-        public Task<List<User>> getSomeUser(int nb, int page);
+        public Task<List<User>?> getSomeUser(int nb, int page);
 
         public Task<User> getOneUser(int id);
 
diff --git a/WF-WebAdmin/WF-WebAdmin/Service/UserServiceStub.cs b/WF-WebAdmin/WF-WebAdmin/Service/UserServiceStub.cs
index d4ca0fd..eaef0a4 100644
--- a/WF-WebAdmin/WF-WebAdmin/Service/UserServiceStub.cs
+++ b/WF-WebAdmin/WF-WebAdmin/Service/UserServiceStub.cs
@@ -55,7 +55,7 @@ public class UserServiceStub : IUserService
     /// This method updates the `IsAdmin` property of the specified user to `true`, indicating that the user is an administrator.
     /// It then calls the <see cref="updateUser"/> method to persist the updated user information.
     /// </remarks>
-    public Task updateRole(User user)
+    public Task updateRole(User? user)
     {
         user.IsAdmin = true;
         return updateUser(user);
@@ -71,7 +71,7 @@ public class UserServiceStub : IUserService
     /// This method updates the `IsAdmin` property of the specified user to `false`, removing their administrator status.
     /// It then calls the <see cref="updateUser"/> method to persist the updated user information.
     /// </remarks>
-    public Task downgradeRole(User user)
+    public Task downgradeRole(User? user)
     {
         user.IsAdmin = false;
         return updateUser(user);
@@ -113,7 +113,7 @@ public class UserServiceStub : IUserService
     /// It returns the corresponding subset of users for the given page. If the page exceeds the available number of users, 
     /// it returns the last `nb` users available.
     /// </remarks>
-    public async Task<List<User>> getSomeUser(int nb, int page)
+    public async Task<List<User>?> getSomeUser(int nb, int page)
     {
         var users = await getAllUser();
         if ((page - 1) * nb + nb > users.Count)
@@ -177,7 +177,7 @@ public class UserServiceStub : IUserService
     /// If a user with the given ID is found, it updates their details (Name, Email, Image, IsAdmin) based on the provided `user` object.
     /// After updating the user, the modified list of users is saved back to the JSON file using the <see cref="saveUsersJson"/> method.
     /// </remarks>
-    public async Task updateUser(User user)
+    public async Task updateUser(User? user)
     {
         var data = await getAllUser();
         var person = data.FirstOrDefault(p => p.Id == user.Id);