private void AAbutton1_Click(object sender, RoutedEventArgs e)
    {

        Account selected = new Account();
        if (textBox2.Text != null)
            selected.username = textBox2.Text;
        if (textBox12.Text != null)
            selected.password = textBox12.Text;
        if (locationTxtBox2.Text != null)
            selected.location = locationTxtBox2.Text;
        MainWindow.Instance.editAccount(selected);
        MainWindow.Instance.updateData();
        MainWindow.Instance.needsSave = true;
    }

public void editAccount(Account acc)
    {
        Account acc2;
        Account selected = (Account)dataGrid.SelectedItem;
        acc2 = Manager.accounts.ElementAt(Manager.accounts.FindIndex(a=> a == selected));
        acc2.username = acc.username;
        acc2.password = acc.password;
        acc2.location = acc.location;
    }

public class Account
{
    public String username { get; set; }
    public String password { get; set; }
    public String location { get; set; }
    public Account(String username,String password, String location)
    {
        this.username = username;
        this.password = password;
        this.location = location;
    }
    public Account()
    {

    }
}