private void OnLoginBtn(object sender, RoutedEventArgs e)
{
var user = DataBaseInterface.Login(XloginBox.Text, XpasswordBox.Password);
if (user != null)
{
DataSaver.CurrentUser = user;
((MainWindow)Application.Current.MainWindow).Navigate(new PPersonalForm());
}
else
{
MessageBox.Show("Введенные данные не верны");
}
}