diff --git a/API_SQLuedo/API/Controllers/UsersController.cs b/API_SQLuedo/API/Controllers/UsersController.cs
index 623360e..1a5b42e 100644
--- a/API_SQLuedo/API/Controllers/UsersController.cs
+++ b/API_SQLuedo/API/Controllers/UsersController.cs
@@ -28,14 +28,14 @@ namespace API.Controllers
         [HttpGet("users/{page}/{number}")]
         public async Task<IActionResult> GetUsers(int page, int number) 
         {
-            var nbUser = (await _dataService.UserService.GetUsers(page, number)).ToList().Count();
+            var nbUser = (await _dataService.UserService.GetItems(page, number)).ToList().Count();
             if(nbUser == 0) 
             {
                 _logger.LogError("[ERREUR] Aucun utilisateur trouvé.");
                 return StatusCode(204);
             }
             _logger.LogInformation("[INFORMATION] {nb} Utilisateur(s) trouvé(s)", nbUser);
-            return Ok(_dataService.UserService.GetItems<UserEntity>(page, number));
+            return Ok(_dataService.UserService.GetItems(page, number));
         }
 
         [HttpGet("user/id/{id}")]
@@ -44,8 +44,8 @@ namespace API.Controllers
             try
             {
                 _logger.LogInformation("[INFORMATION] Utilisateur avec l'id {id} a été trouvé.", id);
-                return Ok(_dataService.UserService.GetItems<UserEntity>(1, 1, UserProperty.Id.ToString(),id));
-            } catch (ArgumentException) 
+                return Ok(_dataService.UserService.GetItems(1, 1, UserProperty.Id.ToString(),id));
+            } catch (KeyNotFoundException) 
             {
                 _logger.LogError("[ERREUR] Aucun utilisateur trouvé avec l'id {id}.", id);
                 return NotFound();
@@ -58,7 +58,7 @@ namespace API.Controllers
             try
             {
                 _logger.LogInformation("[INFORMATION] Utilisateur avec l'username {username} a été trouvé.", username);
-                return Ok(_dataService.UserService.GetItems<UserEntity>(1, 1,UserProperty.Username.ToString(), username));
+                return Ok(_dataService.UserService.GetItems(1, 1,UserProperty.Username.ToString(), username));
             }catch (ArgumentException) 
             {
                 _logger.LogError("[ERREUR] Aucun utilisateur trouvé avec l'username {username}.", username);
@@ -70,11 +70,11 @@ namespace API.Controllers
         [HttpDelete]
         public async Task<IActionResult> DeleteUser(int id)
         {
-            var success = await _dataService.UserService.DeleteItem<UserEntity>(id);
+            var success = await _dataService.UserService.DeleteItem(id);
             if(success)
             {
                 _logger.LogInformation("[INFORMATION] L'utilisateur avec l'id {id} a été supprimé.", id);
-                return Ok(_dataService.UserService.DeleteItem<UserEntity>(id));
+                return Ok(_dataService.UserService.DeleteItem(id));
             } else
             {
                 _logger.LogError("[ERREUR] Aucun utilisateur trouvé avec l'id {id}.", id);
@@ -92,7 +92,7 @@ namespace API.Controllers
             }
 
             _logger.LogInformation("[INFORMATION] Un utilisateur a été créé : username - {username}, password - {password}, email - {email}, isAdmin - {isAdmin}", dto.Username, dto.Password, dto.Email, dto.IsAdmin);
-            return Created(nameof(GetUsers), _dataService.UserService.AddItem(dto.FromDTOToModel().FromModelToEntity()));
+            return Created(nameof(GetUsers), _dataService.UserService.AddItem(dto));
         }
 
         [HttpPut]
@@ -111,7 +111,7 @@ namespace API.Controllers
             if(userDTO != null) 
             {
                 _logger.LogInformation("[INFORMATION] La mise à jour de l'utilisateur avec l'id {id} a été effectuée", id);
-                return Ok(_dataService.UserService.UpdateItem<UserEntity, UserDTO>(id, userDTO));
+                return Ok(_dataService.UserService.UpdateItem<UserDTO>(id, userDTO));
             }
             _logger.LogError("[ERREUR] Aucun utilisateur trouvé avec l'id {id}.", id);
             return NotFound(); 
diff --git a/API_SQLuedo/ModelToEntity/DbDataManager.cs b/API_SQLuedo/ModelToEntity/DbDataManager.cs
index c4640e0..e14f522 100644
--- a/API_SQLuedo/ModelToEntity/DbDataManager.cs
+++ b/API_SQLuedo/ModelToEntity/DbDataManager.cs
@@ -12,7 +12,7 @@ using System.Runtime.InteropServices.ObjectiveC;
 
 namespace ModelToEntity
 {
-    public class DbDataManager : IUserDataService<User>
+    public class DbDataManager : IUserDataService<User?>
     {
         public async Task<User> GetUserById(int id)
         {
@@ -161,37 +161,34 @@ namespace ModelToEntity
             throw new NotImplementedException();
         }
 
-        public async Task<T?> AddItem<T>(T? item) where T : class
+        public async Task<User?> AddItem(User? item)
         {
             using (var context = new UserDbContext())
             {
-                return await context.CreateItemAsync(item);
+                return (await context.CreateItemAsync(item.FromModelToEntity())).FromEntityToModel() ;
             }
-
         }
 
-        public async Task<bool> DeleteItem<T>(int id) where T : class
+        public async Task<bool> DeleteItem(int id)
         {
            using(var context = new UserDbContext())
             {
-                return await context.DeleteItemAsync<T>(id);
+                return await context.DeleteItemAsync<UserEntity>(id);
             }
         }
-        public async Task<T?> UpdateItem<T, TDto>(int? id, TDto? newItem)
-            where T : class
-            where TDto : class
+        public async Task<User?> UpdateItem<TDto>(int? id, TDto? newItem) where TDto : class
         {
             using(var context = new UserDbContext()) 
             {
-                return await context.UpdateItemAsync<T, TDto>(id, newItem);
+                return (await context.UpdateItemAsync<UserEntity, TDto>(id, newItem)).FromEntityToModel();
             }  
         }
 
-        public async Task<IEnumerable<T?>> GetItems<T>(int index, int count, string? orderingPropertyName = null, object? valueProperty = null) where T : class
+        public async Task<IEnumerable<User?>> GetItems(int index, int count, string? orderingPropertyName = null, object? valueProperty = null)
         {
             using (var context = new UserDbContext())
             {
-                return await context.GetItemsWithFilter<T>(index, count, orderingPropertyName, valueProperty);
+                    return (await context.GetItemsWithFilter<UserEntity>(index, count, orderingPropertyName, valueProperty)).Select(item => item.FromEntityToModel());  
             }
         }
     }  
diff --git a/API_SQLuedo/ModelToEntity/Extension.cs b/API_SQLuedo/ModelToEntity/Extension.cs
index 02c8edd..12ea2d6 100644
--- a/API_SQLuedo/ModelToEntity/Extension.cs
+++ b/API_SQLuedo/ModelToEntity/Extension.cs
@@ -56,9 +56,11 @@ namespace ModelToEntity
             {
                 throw new ArgumentException("Impossible de trouver l'entité", nameof(id));
             }
+            var primaryKey = context.Model.FindEntityType(typeof(T)).FindPrimaryKey();
+            var primaryKeyPropertyName = primaryKey.Properties.Select(x => x.Name).Single();
 
             var propertiesToUpdate = typeof(TDto).GetProperties()
-                                                  .Where(p => p.CanRead && p.CanWrite);
+                                                  .Where(p => p.CanRead && p.CanWrite && p.Name != primaryKeyPropertyName);
 
             foreach (var property in propertiesToUpdate)
             {
@@ -72,7 +74,7 @@ namespace ModelToEntity
             return Task.FromResult<T?>(entity);
         }
         internal static Task<IEnumerable<T?>> GetItemsWithFilter<T>(this DbContext context,
-            int index, int count, string? orderingPropertyName = null, object valueProperty = null) where T : class
+            int index, int count, string? orderingPropertyName = null, object? valueProperty = null) where T : class
         {
             IQueryable<T> query = context.Set<T>();
 
@@ -96,6 +98,7 @@ namespace ModelToEntity
                         }
                     }
                 }
+                return Task.FromResult<IEnumerable<T?>>(new List<T?> { default(T) });
             }
             var items = query.Skip(index).Take(count).ToList();
             return Task.FromResult<IEnumerable<T?>>(items);
diff --git a/API_SQLuedo/Services/UserDataService.cs b/API_SQLuedo/Services/UserDataService.cs
index 82d6c0d..9a27067 100644
--- a/API_SQLuedo/Services/UserDataService.cs
+++ b/API_SQLuedo/Services/UserDataService.cs
@@ -56,28 +56,36 @@ namespace Services
             return newUserEntity.FromModelToDTO();
         }
 
-        public async Task<T?> AddItem<T>(T? item) where T : class
+        public async Task<UserDTO?> AddItem(UserDTO? item)
         {
-            var newItem = dataServiceEF.AddItem(item);
-            return await newItem;
+            var newItem = await dataServiceEF.AddItem(item.FromDTOToModel());
+            return newItem.FromModelToDTO();
         }
 
-        public Task<bool> DeleteItem<T>(int id) where T : class
+        public Task<bool> DeleteItem(int id)
         {
-            var succes = dataServiceEF.DeleteItem<T>(id);
+            var succes = dataServiceEF.DeleteItem(id);
             return succes;
         }
 
-        public Task<T> UpdateItem<T, TDto>(int? id, TDto? newItem) where T : class where TDto : class
+        public async Task<UserDTO> UpdateItem<TDto>(int? id, TDto? newItem) where TDto : class
         {
-            var item = dataServiceEF.UpdateItem<T, TDto>(id, newItem);
-            return item;
+            var item = await dataServiceEF.UpdateItem<TDto>(id, newItem);
+            return item.FromModelToDTO();
         }
 
-        public Task<IEnumerable<T?>> GetItems<T>(int index, int count, string? orderingPropertyName = null, object? valueProperty = null) where T : class
+        public async Task<IEnumerable<UserDTO?>> GetItems(int index, int count, string? orderingPropertyName = null, object? valueProperty = null)
         {
-           var items = dataServiceEF.GetItems<T>(index, count, orderingPropertyName, valueProperty);
-            return items;
+            try
+            {
+                var items = await dataServiceEF.GetItems(index, count, orderingPropertyName, valueProperty);
+                return items.Select(item => item.FromModelToDTO());
+            }
+            catch (KeyNotFoundException ex)
+            {
+                throw;
+            }
+
         }
 
         public Task<IEnumerable<ParagraphDTO>> GetParagraphs(int page, int number)
diff --git a/API_SQLuedo/Shared/IGenericService.cs b/API_SQLuedo/Shared/IGenericService.cs
index 4e84eaf..c047693 100644
--- a/API_SQLuedo/Shared/IGenericService.cs
+++ b/API_SQLuedo/Shared/IGenericService.cs
@@ -2,9 +2,9 @@
 {
     public interface IGenericService<T> where T : class
     {
-        public Task<T?> AddItem<T>(T? item) where T : class;
-        public Task<bool> DeleteItem<T>(int id) where T : class;
-        public Task<T> UpdateItem<T, TDto>(int? id, TDto? newItem) where T : class where TDto : class;
-        public Task<IEnumerable<T>> GetItems<T>(int index, int count, string? orderingPropertyName = null, object? valueProperty = null) where T : class;
+        public Task<T?> AddItem(T? item);
+        public Task<bool> DeleteItem(int id);
+        public Task<T> UpdateItem<TDto>(int? id, TDto? newItem) where TDto : class;
+        public Task<IEnumerable<T>> GetItems(int index, int count, string? orderingPropertyName = null, object? valueProperty = null);
     }
 }