private void Login_Button_Click(object sender, RoutedEventArgs e) { FileReadWrite file = new FileReadWrite(); if (usernameTB.Text.Trim() == "" && passwordBox.Password == "") { MessageBox.Show("Please enter Username and Password."); } else { if (file.readStudentFromFile(student, usernameTB.Text.Trim(), passwordBox.Password.Trim())) { file.ReadDataFromFile(student); homeScreen studentForm = new homeScreen(student); this.Close(); studentForm.ShowDialog(); } else { MessageBox.Show("Username and password is incorrect."); } } }