笔记:C# 中简易的登录与注册(SQL)

注册

        private void a_reg_Click(object sender, EventArgs e)
        {
            string a = a_accout.Text.Replace(" ", "");
            string p = a_password.Text.Replace(" ", "");
            Regex reg = new Regex("^[A-Za-z0-9]+$");
            try
            {
                if (!reg.IsMatch(p) || !reg.IsMatch(a))
                {
                    MessageBox.Show("账户或密码格式错误!\nPs:只能使用数字或英文!", "错误");
                }
                else
                {
                    string Cmd_Reg = "INSERT INTO UserDB (UserName,PassWord) VALUES ('" + a + "','" + p + "');";
                    SqlConnection con = new SqlConnection("server=;user=;pwd=;database=;");
                    con.Open();

                    SqlCommand com = new SqlCommand();
                    com.Connection = con;
                    com.CommandType = CommandType.Text;
                    com.CommandText = Cmd_Reg;
                    com.ExecuteNonQuery();
                    // SqlDataReader dr = com.ExecuteReader();
                    //dr.Close();

                    con.Close();
                    MessageBox.Show("注册成功,请保存好您的账号密码\n账号:"+a+"\n密码:"+p, "提示");
                }
            }
            catch(SqlException error)
            {
                //MessageBox.Show(error.ToString(), "错误");
                DialogResult DR = MessageBox.Show("系统错误\n1)请检查账号密码是否填写\n2)请检查账号密码是否重复\n点击[否]打开错误日志)", "错误", MessageBoxButtons.YesNo);
                if(DR == DialogResult.No)
                {
                    MessageBox.Show(error.ToString(),"错误信息");
                }
            }
        }

登录

        private void a_login_Click(object sender, EventArgs e)
        {
            try
            {
                string a = a_accout.Text.Replace(" ", "");
                string p = a_password.Text.Replace(" ", "");
                
               // MessageBox.Show(p); 调试
                string Cmd_Login = "SELECT * FROM UserDB WHERE UserName='" +  a + "' AND PassWord = '" + p + "';";
                SqlConnection con = new SqlConnection("server=;user=;pwd=;database=;");
                con.Open();
                SqlCommand com = new SqlCommand();
                com.Connection = con;
                com.CommandType = CommandType.Text;
                com.CommandText = Cmd_Login;
                SqlDataReader reader = com.ExecuteReader();
                string DbPassword=null;
                while (reader.Read())//数据获取
                {
                    Level = reader.GetString(reader.GetOrdinal("Level"));
                   // a_level.Text = "權限組:"+Level;
                    DbPassword = reader.GetString(reader.GetOrdinal("PassWord"));
                }

                if (DbPassword == a_password.Text)
                {
                    Login();
                }
                else
                {
                    MessageBox.Show("账号密码错误!", "账号错误");
                }
                con.Close();
            }
            catch(SqlException error)
            {
                MessageBox.Show(error.ToString(), "系统错误");
            }
        }