private void btnSave_Click(object sender, EventArgs e)
 {
     if (ValidateChildren(ValidationConstraints.Enabled) && userIdentity.ChangePassword(UserIdentity.SessionUser.UserName, txbUsername.Text, textEdit1.Text))
     {
         XtraMessageBox.Show("Change password successfully!", "Success");
         this.DialogResult = DialogResult.OK;
         this.Close();
     }
     else
     {
         XtraMessageBox.Show("Wrong password", "ERROR");
     }
 }