Entity Framework Core
A lightweight, extensible, open-source, and cross-platform version of the Entity Framework data access technology.
696 questions
EF - checking that an user cannot enter twice the same key - 12 pgms - 8 working well, 4 send an system error msg !!!
![](data:image/svg+xml, %3Csvg xmlns='http://www.w3.org/2000/svg' height='64' class='font-weight-bold' style='font: 600 30.11764705882353px "SegoeUI", Arial' width='64'%3E%3Ccircle fill='hsl(44.800000000000004, 28.999999999999996%, 14%)' cx='32' cy='32' r='32' /%3E%3Ctext x='50%25' y='55%25' dominant-baseline='middle' text-anchor='middle' fill='%23FFF' %3ED%3C/text%3E%3C/svg%3E)
Dmtr_Grms
331
Reputation points
Could someone help me? How to catch that kind of exception? I cannot find the InnerException message number as for example with DBupdateException.
Thanks in advance for your help.
Error msg: System.InvalidOperationException: 'The instance of entity type 'Country' cannot be tracked because another instance with the same key value for {'CountryName'} is already being tracked. When attaching existing entities, ensure that only one entity instance with a given key value is attached. Consider using 'DbContextOptionsBuilder.EnableSensitiveDataLogging' to see the conflicting key values.'
class:
using System.ComponentModel.DataAnnotations;
using System;
using System.Collections.Generic;
namespace ATChome.DbModel
{
public class Country
{
public int CountryId { get; set; }
public string CountryName { get; set; }
public string CountryIso { get; set; }
public bool IsDeleted { get; set; }
public int UserIdCrea { get; set; }
public DateTime DateCreation { get; set; }
public int UserIdMod { get; set; }
public DateTime DateModification { get; set; }
public byte[] Timestamp { get; set; }
// Relationship Collection Navigation Property
public List<Postalinfo> Postalinfos { get; set; }
}
}
DBContext:
public DbSet<Country>? Countries { get; set; }
// COUNTRY Table
modelBuilder.Entity<Country>().HasKey(c => c.CountryId);
modelBuilder.Entity<Country>().HasIndex(c => c.CountryName).IsUnique();
modelBuilder.Entity<Country>().Property(c => c.CountryName).HasMaxLength(60);
modelBuilder.Entity<Country>().Property(c => c.CountryIso).HasMaxLength(3);
modelBuilder.Entity<Country>().Property(c => c.IsDeleted).HasDefaultValue(0);
modelBuilder.Entity<Country>().Property(c => c.UserIdCrea);
modelBuilder.Entity<Country>().Property(c => c.DateCreation).HasDefaultValueSql("getdate()");
modelBuilder.Entity<Country>().Property(c => c.UserIdMod);
modelBuilder.Entity<Country>().Property(c => c.DateModification).HasDefaultValueSql("getdate()");
modelBuilder.Entity<Country>().Property(c => c.Timestamp).IsRowVersion();
Program C#:
using ATChome.DbModel;
using Microsoft.EntityFrameworkCore;
using System;
using System.ComponentModel;
using System.Data;
using System.Linq;
using System.Windows;
using System.Windows.Controls;
// Imports necessary to add
using System.Windows.Data;
using Microsoft.Data.SqlClient;
namespace ATChome
{
/// <summary>
/// Interaction logic for PageCountries.xaml
/// </summary>
public partial class PageCountries : Window
{
// Context initialization
private readonly AtcDbContext context = new();
Country NewCountry = new();
// WARNING - put readonly in order to avoid message from compiler controls
private readonly CollectionViewSource countryViewSource;
public PageCountries()
{
this.context = context;
InitializeComponent();
countryViewSource = (CollectionViewSource)FindResource(nameof(countryViewSource));
GvAdd.DataContext = NewCountry;
}
private void Window_Loaded(object sender, RoutedEventArgs e)
{
// Load the entities into EF Core
context.Countries.Load();
// Binding to the source
countryViewSource.Source = context.Countries.Local.ToObservableCollection();
}
// Filters Box Collection and Refresh Management
// Filter on CountryName
private void TxtCountryName_TextChanged(object sender, TextChangedEventArgs e)
{
// Refresh the view to apply filters.
CollectionViewSource.GetDefaultView(DataGridList.ItemsSource).Refresh();
}
// Filter on CountryIso
private void TxtCountryIso_TextChanged(object sender, TextChangedEventArgs e)
{
// Refresh the view to apply filters.
CollectionViewSource.GetDefaultView(DataGridList.ItemsSource).Refresh();
}
// Filter on IsDeleted refresh
private void IsDeletedFilter_Changed(object sender, RoutedEventArgs e)
{
// Refresh the view to apply filters.
CollectionViewSource.GetDefaultView(DataGridList.ItemsSource).Refresh();
}
private void CollectionViewSource_Filter(object sender, FilterEventArgs e)
{
int refused = 0;
if (e.Item is Country t && t != null) /* If filters have value, process filters.
WARNING introduced comparison type for Culture params and NON sensitive Case */
{
if (this.TxtCountryName != null && t.CountryName != null && t.CountryName.Contains(TxtCountryName.Text, StringComparison.CurrentCultureIgnoreCase) == false)
{
refused++;
}
if (this.TxtCountryIso != null && t.CountryIso != null && t.CountryIso.Contains(TxtCountryIso.Text, StringComparison.CurrentCultureIgnoreCase) == false)
{
refused++;
}
if (this.CbIsDeletedFilter.IsChecked == false && t.IsDeleted == true)
{
refused++;
}
if (refused == 0)
{
e.Accepted = true;
}
else
{
e.Accepted = false;
}
}
}
// - Event handler for Selection in DataGrid -
private void DataGridList_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
if (e.AddedItems.Count > 0)
{
Country country = (Country)e.AddedItems[0];
if (country.IsDeleted == true)
{
DataGridList.SelectedItem = null;
CollectionViewSource.GetDefaultView(DataGridList.ItemsSource).Refresh();
MessageBox.Show("Non è possibile modificare un Paese cancellato", "ATC - ERRORE", MessageBoxButton.OK, MessageBoxImage.Error);
return;
}
}
}
//Event handler for the UI Update Button in Tabcontrol.
private void BtnUpdate1_Click(object sender, RoutedEventArgs e)
{
int mistakeinupdate = 0;
if (string.IsNullOrWhiteSpace(TxtCountryName1.Text))
{
mistakeinupdate = 1;
MessageBox.Show("Inserire un nome Paese per favore", "ATC - ERRORE", MessageBoxButton.OK, MessageBoxImage.Error);
}
if (string.IsNullOrWhiteSpace(TxtCountryIso1.Text))
{
mistakeinupdate = 2;
MessageBox.Show("Inserire un Codice ISO per favore", "ATC - ATC - ERRORE", MessageBoxButton.OK, MessageBoxImage.Error);
}
if (mistakeinupdate == 0)
{
// Before Save in DB - Context Update because trigger choice in XAML is Explicit !
BindingExpression be1 = TxtCountryName1.GetBindingExpression(TextBox.TextProperty);
be1.UpdateSource();
BindingExpression be2 = TxtCountryIso1.GetBindingExpression(TextBox.TextProperty);
be2.UpdateSource();
try
{
context.SaveChanges();
// Deselect Item and Refresh all views .
DataGridList.SelectedItem = null;
CollectionViewSource.GetDefaultView(DataGridList.ItemsSource).Refresh();
MessageBox.Show("Paese modificato correttamente", "ATC - CONFERMA", MessageBoxButton.OK, MessageBoxImage.Information);
}
catch (DbUpdateException)
{
MessageBox.Show("Problema aggiornamento DataBase in modifica", "ATC - ERRORE", MessageBoxButton.OK, MessageBoxImage.Error);
}
catch (DBConcurrencyException ex)
{
MessageBox.Show("Non posso aggiornare il DataBase un altro utente lo sta modificando, riprovare per favore", "ATC - ERRORE", MessageBoxButton.OK, MessageBoxImage.Error);
// Deselect Item and Refresh all views .
DataGridList.SelectedItem = null;
CollectionViewSource.GetDefaultView(DataGridList.ItemsSource).Refresh();
}
}
else
{
return;
}
}
//Event handler for the UI Add Button in Tabcontrol.
private void BtnAdd0_Click(object sender, RoutedEventArgs e)
{
// Initialization
// Check data coming from ADD GUI
int mistakeinadd = 0;
if (string.IsNullOrWhiteSpace(TxtCountryName0.Text))
{
mistakeinadd = 1;
MessageBox.Show("Inserire un nome Paese per favore", "ATC - ERRORE", MessageBoxButton.OK, MessageBoxImage.Error);
}
if (string.IsNullOrWhiteSpace(TxtCountryIso0.Text))
{
mistakeinadd = 2;
MessageBox.Show("Inserire un Codice ISO per favore", "ATC - ATC - ERRORE", MessageBoxButton.OK, MessageBoxImage.Error);
}
// Insert in Database
if (mistakeinadd == 0)
{
try
{
****context.Countries.Add(NewCountry);** LINE THAT GIVES ERROR!!!!!!!!!!!!**
context.SaveChanges();
DataGridList.SelectedItem = null;
CollectionViewSource.GetDefaultView(DataGridList.ItemsSource).Refresh();
NewCountry = new Country();
GvAdd.DataContext = NewCountry;
MessageBox.Show("Paese aggiunto correttamente", "ATC - CONFERMA", MessageBoxButton.OK, MessageBoxImage.Information);
}
catch (DbUpdateException ex)
{
if (ex.InnerException is SqlException sqlException)
{
switch (sqlException.Number)
{
case 2601: // Unique Key violation exception code
context.Countries.Remove(NewCountry);
MessageBox.Show("Paese già esistente", "ATC - ERRORE", MessageBoxButton.OK, MessageBoxImage.Error);
break;
default:
context.Countries.Remove(NewCountry);
MessageBox.Show("Problema aggiornamento DataBase, contattare supporto", "ATC - ERRORE", MessageBoxButton.OK, MessageBoxImage.Error);
break;
}
}
}
}
else
{
return;
}
}
// Event handler for the UI Logical Cancel Button in Tabcontrol.
private void BtnCancel1_Click(object sender, RoutedEventArgs e)
{
if (string.IsNullOrWhiteSpace(TxtCountryName1.Text))
{
return;
}
else
{
if (MessageBox.Show("Cancellare il Paese ?", "ATC - CONFERMA", MessageBoxButton.YesNo, MessageBoxImage.Exclamation) == MessageBoxResult.Yes)
{
CbIsDeleted1.IsChecked = true;
context.SaveChanges();
// Deselect Item and Refresh all views .
DataGridList.SelectedItem = null;
CollectionViewSource.GetDefaultView(DataGridList.ItemsSource).Refresh();
MessageBox.Show("Paese cancellato", "ATC - CONFERMA", MessageBoxButton.OK, MessageBoxImage.Information);
}
else
{
return;
}
}
}
// CLOSING Procedure
//Close current PageCountries page with Button.
private void ClosePageCountries_Click(object sender, RoutedEventArgs e)
{
context.Dispose();
this.Close();
}
// Clean up connections when closing window.
protected override void OnClosing(CancelEventArgs e)
{
// clean up database connections
context.Dispose();
}
}
}
{count} votes
-
Jack J Jun 24,296 Reputation points Microsoft Vendor2022-08-08T08:40:39.123+00:00 @Dmtr_Grms , Welcome to Microsoft Q&A, the error means that you set the same CountryName for different Country entities. I didn't see the related code about how to set the NewCountry properties, Could you provide it? Also, you could put a breakpoint in the error line to check if the CountryName already exists in the database.
-
Dmtr_Grms 331 Reputation points
2022-08-09T08:08:13.837+00:00 Thanks foy your answer. I debbuged the program before to write my post. I know that I'm inserting a CountryName that already exist, it is what I'm testing in my program (see above line 176). I wrote 12 programs with the same code, 8 are running perfectly and send the msg. 4 are not working. They come with the error message indicated at the beginning of my post. I don't understand why for exactly the same test case the 8 working programs send a SQL Exception and why the four not working sends an Entity Framework exception. The code is the one that you can see in my post. The Add routine starts in line 139 and stops in line 162 with EF error msg. Thanks in advance for your help.
Sign in to comment