My application freeze when loading information from my database (no replies)

Hello, i have a annoying bug when i try to reach the database server, my application freeze.

I have searched and come down with the background worker and i done it but it keeps freezing for a couple seconds.

You have a great help voor me earlier so i hope that you guys can help me.

private readonly BackgroundWorker worker = new BackgroundWorker();


private void Window_Loaded(object sender, RoutedEventArgs e)
{
worker.DoWork += worker_DoWork;
worker.RunWorkerCompleted += worker_RunWorkerCompleted;
worker.RunWorkerAsync();
}

private void worker_DoWork(object sender, DoWorkEventArgs e)
{
Dispatcher.Invoke(new Action(() =>
{
conn4.Open();
MySqlCommand cmd = new MySqlCommand("Select ID,Voornaam,Achternaam,Gebruikersnaam,Wachtwoord,Email,Taal from Gebruikers", conn);
MySqlDataAdapter adp = new MySqlDataAdapter(cmd);
DataSet ds = new DataSet();
adp.Fill(ds, "LoadDataBinding");
dataGridCustomers.DataContext = ds;
conn4.Close();
label.Content = dataGridCustomers.Items.Count - (1);
int number = Convert.ToInt32(label.Content);
number = number + 1;
label.Content = number.ToString();
}));
}

private void worker_RunWorkerCompleted(object sender,
RunWorkerCompletedEventArgs e)
{
//checking for username and email
}

Sorry for my bad english.

Greetings from the Netherlands.