Program in WPF C# using .mdf database with LINQtoSQL freezes for a bit when I load the database

Question

Hello everyone, I have the following code that I run inside a button clicked event in order to compare the username and password
given by the user.
public static bool isAuthenticated(string Username, string Password)
//Open a connection with the databas
using (WHDataDataContext db = new WHDataDataContext())
//Compare the Username and the password and return the result
return db.Users.Any(check => check.Username == Username && check.Password == Cryptographer.Encrypt(Password));
and I use the code like this
private void Button_Click(object sender, RoutedEventArgs e)
//Access the DatabaseControls class and use the isAuthenticated Method
if (DatabaseControls.isAuthenticated(UserBox.Text, PasswordBox.Password))
DialogResult = true; //if the result is true close the dialog
DatabaseControls.setConnected(UserBox.Text, true);
else if (UserBox.Text == "" || PasswordBox.Password == "")
//if the user didn't fill any of the requested boxes show warning
MessageBox.Show(this, "Το όνομα χρήστη και ο κωδικός δεν μπορούν να είναι άδεια", "Προσοχή!", MessageBoxButton.OK, MessageBoxImage.Warning);
if (UserBox.Text == "") UserBox.Focus(); //if the UserBox was empty focus it
else PasswordBox.Focus(); //else focus the PasswordBox
else
//if the result is false show an error and select the UserBox
MessageBox.Show(this, "Δώσατε λάθος στοιχεία, παρακαλώ προσπαθήστε ξανά!", "Σφάλμα", MessageBoxButton.OK, MessageBoxImage.Error);
UserBox.SelectAll();
UserBox.Focus();
My problem is that when I hit the button the program freezes for a moment and the it responds.
I have used this code on a c# application with .sdf file (SQL CE) and I haven't experienced this issue.
I have already tried using threads (Task.StartNew and BackgroundWorker) but I got the same result.
I have also created the DB Context once instead of using (DBContext db = new DBContext()) everytime and I still got the same result.
Could anyone please help?

Answer 1

Async features should have addressed it, you may not just be doing things properly.
Try implementing things this way:
1. If you're not using EF 6 which is the latest version then update your project first. This will allow you to take advantage of EF's async methods.
2. Implement your isAuthenticated method in this manner:
public static Task<bool> isAuthenticatedAsync(string Username, string Password)
//Open a connection with the databas
using (WHDataDataContext db = new WHDataDataContext())
//Compare the Username and the password and return the result
return db.Users.AnyAsync(check => check.Username == Username && check.Password == Cryptographer.Encrypt(Password));
3. Implement your Button_Click event handler in this manner:
private async void Button_Click(object sender, RoutedEventArgs e)
//Access the DatabaseControls class and use the isAuthenticated Method
var authenticated = await DatabaseControls.isAuthenticatedAsync(UserBox.Text, PasswordBox.Password);
if (authenticated)
DialogResult = true; //if the result is true close the dialog
DatabaseControls.setConnected(UserBox.Text, true);
else if (UserBox.Text == "" || PasswordBox.Password == "")
//if the user didn't fill any of the requested boxes show warning
MessageBox.Show(this, "Το όνομα χρήστη και ο κωδικός δεν μπορούν να είναι άδεια", "Προσοχή!", MessageBoxButton.OK, MessageBoxImage.Warning);
if (UserBox.Text == "") UserBox.Focus(); //if the UserBox was empty focus it
else PasswordBox.Focus(); //else focus the PasswordBox
else
//if the result is false show an error and select the UserBox
MessageBox.Show(this, "Δώσατε λάθος στοιχεία, παρακαλώ προσπαθήστε ξανά!", "Σφάλμα", MessageBoxButton.OK, MessageBoxImage.Error);
UserBox.SelectAll();
UserBox.Focus();