private void LogIn()
        {
            bool usernameCorrect = false;
            AccountVM Account = new AccountVM();
            foreach (AccountVM account in Accounts)
            {
                if (account.Username.ToLower().Equals(Username.ToLower()))
                {
                    usernameCorrect = true;
                    Account = account;
                    break;
                }
            }
            if (!usernameCorrect)
            {
                MessageBox.Show("De gebruiksnaam bestaat niet!", "Gebruikersnaam incorrect!", MessageBoxButton.OK, MessageBoxImage.Error);
                return;
            }

            bool passwordCorrect = false;
            if (Account.Password.Equals(Password))
                passwordCorrect = true;
            if(!passwordCorrect)
            {
                MessageBox.Show("Het wachtwoord klopt niet", "Wachtwoord incorrect!", MessageBoxButton.OK, MessageBoxImage.Error);
                return;
            }

            if(usernameCorrect && passwordCorrect)
            {
                MainWindow i = new MainWindow();
                MainViewModel a = new MainViewModel();
                i.DataContext = a;
                i.Show();
                CloseWindow();
                return;
            }
            else
            {
                MessageBox.Show("Error occured!", "ERROR!", MessageBoxButton.OK, MessageBoxImage.Error);
                return;
            }
        }
 private void clearItem()
 {
     SelectedAccount = new AccountVM();
 }