private void btnSubmit_Click(object sender, RoutedEventArgs e)
        {
            if (txtEmail.Text.Length < 7 || txtEmail.Text.Length > 250)
            {
                MessageBox.Show("The email you submitted was invalid. Please try again.");
                txtEmail.Focus();
                txtEmail.SelectAll();
                return;
            }

            if (pwdOldPassword.Password.Length < 6)
            {
                MessageBox.Show("The old password you submitted was invalid. Please try again.");
                pwdOldPassword.Focus();
                pwdOldPassword.SelectAll();
                return;
            }

            if (pwdNewPassword.Password.Length < 6)
            {
                MessageBox.Show("The new password you submitted was invalid. Please try again.");
                pwdNewPassword.Focus();
                pwdNewPassword.SelectAll();
                return;
            }

            if (string.Compare(pwdNewPassword.Password.ToString(), pwdRetypePassword.Password.ToString()) != 0)
            {
                MessageBox.Show("New Password and Retyped Password must match. Please try again.");
                pwdRetypePassword.Password = "******";
                pwdNewPassword.Focus();
                pwdNewPassword.SelectAll();
                return;
            }

            string oldPassword = pwdOldPassword.Password;
            string newPassword = pwdNewPassword.Password;
            string username    = txtEmail.Text;

            try
            {
                if (_userManager.UpdatePasswordSLP(username, oldPassword, newPassword))
                {
                    MessageBox.Show("Password Updated.");
                    _userManager.RefreshSLPUsers(_slpUser, username);
                    this.DialogResult = true;
                }
                else if (_userManager.UpdatePasswordTeacher(username, oldPassword, newPassword))
                {
                    MessageBox.Show("Password Updated.");
                    _userManager.RefreshTeacherUsers(_teacherUser, username);
                    this.DialogResult = true;
                }
                else if (_userManager.UpdatePasswordManager(username, oldPassword, newPassword))
                {
                    MessageBox.Show("Password Updated.");
                    _userManager.RefreshManagerUsers(_managerUser, username);
                    this.DialogResult = true;
                }
            }
            catch (Exception)
            {
                throw;
            }
        }