private void btnLogin_Click(object sender, EventArgs e)
        {
            try
            {
                using (ServiceReference1.UserServiceClient client = new ServiceReference1.UserServiceClient())
                {
                    bool bOK = client.Login(txtUserName.Text.Trim(), txtPassword.Text.Trim());//报错了
                    if (bOK == true)
                    {
                        MessageBox.Show("aaaa");
                    }
                    else
                    {
                        MessageBox.Show("登录失败，可能是用户名或密码不正确！");
                    }
                }
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
            }
        }