private void btnLogin_Click(object sender, EventArgs e) { Users user = new Users(); string username = txbUserName.Text.Trim(); string password = txbPassword.Text.Trim(); UserBusinessLogic usersLogicBusiness = new UserBusinessLogic(); user = usersLogicBusiness.GetUsersByUsername(username); if (user == null) { MessageBox.Show("该用户不存在!"); } else { byte[] input = Encoding.Default.GetBytes(this.txbPassword.Text.Trim()); MD5 md5 = new MD5CryptoServiceProvider(); byte[] output = md5.ComputeHash(input); password = BitConverter.ToString(output).Replace("-", ""); if (user.Password == password) { this.Hide(); MainForm mainForm = new MainForm(user.UserID, this); mainForm.Show(); } else { MessageBox.Show("密码不正确,请重新输入!"); } } }