อยากทรายวิธี อ่านเฉพาะบรรทัด ใน txt ครับ แล้ว สามารถแก้ค่าได้ด้วย

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO;

namespace member_module
{
    struct member_db{
            //public int id_customer;
            public string name_customer;
            public string pid_customer;
            public string sex_customer;
            public int age_customer;
            public string address_customer;
            public int main_id;
        };

    class Program
    {



        public static void Main(string[] args)
        {

            int id_customer;
            int count_if;

            Console.WriteLine("Member Module");
            
            check_filemember(out id_customer, out count_if);

            find_member_module();






            new_member_module(ref id_customer, ref count_if);

            Console.WriteLine("End!!!!");


           


        }

        private static void find_member_module()
        {
            Console.Write("Member find Module \n");
            Console.Write(" Menu-----> \nFind ID = ID\nFind Name = Name\nFindPersonal ID = personalid\n");
            Console.Write("Enter mode : ");
            string check;
            check = Console.ReadLine();


            //ID find
            if (check == "ID" || check == "Id" || check == "id" || check == "iD")
            {
                string check_input = null,check_input_parse2=null;
                int count_line = 0;

                Console.Write("ID to find : ");
                check_input = Console.ReadLine();
                check_input_parse2 = "ID : " + check_input;


                string[] readText = File.ReadAllLines("member.txt", Encoding.UTF8);

                foreach (string s in readText)
                {
                    if (s == check_input_parse2)
                    {
                        Console.WriteLine(s);
                        count_line++;

                    }
                    else if (count_line == 1)
                    {
                        Console.WriteLine(s);
                        count_line++;
                    }
                    else if (count_line == 2)
                    {
                        Console.WriteLine(s);
                        count_line++;
                    }
                    else if (count_line == 3)
                    {
                        Console.WriteLine(s);
                        count_line++;
                    }
                    else if (count_line == 4)
                    {
                        Console.WriteLine(s);
                        count_line++;
                    }
                    else if (count_line == 5)
                    {
                        Console.WriteLine(s);
                        count_line++;
                    }


                }

            }


            //name find
            if (check == "Name" || check == "name" || check == "n" || check == "NAME")
            {
                string check_input = null, check_input_parse2 = null;
                int count_line = 0, count_id = 0;

                Console.Write("ID to find : ");
                check_input = Console.ReadLine();
                check_input_parse2 = "Name : " + check_input;


                string[] readText = File.ReadAllLines("member.txt", Encoding.UTF8);

                foreach (string s in readText)
                {
                    count_id++;
                    if (count_id == 7)
                    {
                        Console.WriteLine(s);

                    }
                    else if (s == check_input_parse2)
                    {
                        Console.WriteLine(s);
                        count_line++;

                    }
                    else if (count_line == 1)
                    {
                        Console.WriteLine(s);
                        count_line++;
                    }
                    else if (count_line == 2)
                    {
                        Console.WriteLine(s);
                        count_line++;
                    }
                    else if (count_line == 3)
                    {
                        Console.WriteLine(s);
                        count_line++;
                    }
                    else if (count_line == 4)
                    {
                        Console.WriteLine(s);
                        count_line++;
                    }

                }
            }


            //Personal ID find
                if (check == "Personal ID" || check == "personalid" || check == "p" || check == "personalid")
            {
                string check_input = null, check_input_parse2 = null;
                int count_line = 0,count_id=0;

                Console.Write("Personal ID to find : ");
                check_input = Console.ReadLine();
                check_input_parse2 = "Personal ID : " + check_input;


                string[] readText = File.ReadAllLines("member.txt", Encoding.UTF8);

                foreach (string s in readText)
                {
                    count_id++;
                    if (count_id==7)
                    {
                        Console.WriteLine(s);
                        
                    }
                    if (count_id == 8)
                    {
                        Console.WriteLine(s);
                    }
                    else if (s == check_input_parse2)
                    {
                        Console.WriteLine(s);
                        count_line++;

                    }
                    else if (count_line == 1)
                    {
                        Console.WriteLine(s);
                        count_line++;
                    }
                    else if (count_line == 2)
                    {
                        Console.WriteLine(s);
                        count_line++;
                    }
                    else if (count_line == 3)
                    {
                        Console.WriteLine(s);
                        count_line++;
                    }


                }

            }
        }

        //ระบบเช็กไฟล์ txt สมาชิก
        private static void check_filemember(out int id_customer, out int count_if)
        {
            if (File.Exists("id_customer_txt.txt"))
            {
                string con;
                Console.WriteLine(" [id_customer_txt.txt] ---> already exists!");
                con = File.ReadAllText("id_customer_txt.txt");
                id_customer = Convert.ToInt32(con);
                Convert.ToInt32(id_customer);
                count_if = 0;

            }
            else
            {
                id_customer = 1;
                count_if = 0;

            }
        }


        //ระบบสมัครสมาชิก
        private static void new_member_module(ref int id_customer, ref int count_if)
        {
            string checker, exit;
            member_db a;
            a.main_id = id_customer;
            member_db[] inp = new member_db[id_customer];

            Console.Write("New Member? (Y/N): ");
            checker = Console.ReadLine();
            if (checker == "Y" || checker == "y" || checker == "yes" || checker == "Yes" || checker == "YES")
            {
                count_if = +1;
            }
            else
            {
                return;
            }
            for (int che = count_if; che > 0; che--)
            {
                for (int i = 0; i < id_customer; i = id_customer + 1)
                {

                    StreamWriter txtmember = File.AppendText("member.txt");
                    
                    string fileparth = "id_customer_txt.txt";
                    string filecon = Convert.ToString(id_customer);
                    File.WriteAllText(fileparth, filecon);

                    Convert.ToInt32(id_customer);

                    Console.WriteLine("a Newmember");
                    Console.Write("Please insert name : ");
                    inp[i].name_customer = Console.ReadLine();
                    Console.Write("Please insert Personal-ID : ");
                    inp[i].pid_customer = Console.ReadLine();

                    Console.Write("Please insert sex (M/F) : ");
                    inp[i].sex_customer = Console.ReadLine();
                    //while (inp[i].sex_customer != "M" || inp[i].sex_customer != "F")
                    //{
                    //    Console.Write("Please insert sex again (M/F) : ");
                    //    inp[i].sex_customer = Console.ReadLine();
                    //}

                    Console.Write("Please insert age : ");
                    inp[i].age_customer = int.Parse(Console.ReadLine());
                    //while (inp[i].age_customer < 0 && inp[i].age_customer > 99)
                    //{
                    //    Console.Write("Please insert age again able 0 - 99: ");
                    //    inp[i].age_customer = int.Parse(Console.ReadLine());
                    //}

                    Console.Write("Please insert address : ");
                    inp[i].address_customer = Console.ReadLine();

                    txtmember.WriteLine("ID : {0}", id_customer);
                    txtmember.WriteLine("Name : {0}", inp[i].name_customer);
                    txtmember.WriteLine("Personal ID : {0}", inp[i].pid_customer);
                    txtmember.WriteLine("Sex : {0}", inp[i].sex_customer);
                    txtmember.WriteLine("Age : {0}", inp[i].age_customer);
                    txtmember.WriteLine("Address : {0}", inp[i].address_customer);


                    //id_customer_txt2.Write(Convert.ToString(id_customer));


                    txtmember.Close();
                    //id_customer_txt2.Close();
                    id_customer++;




                }

                Console.Write("Exit ? : ");
                exit = Console.ReadLine();
                if (exit == "N" || exit == "n")
                {
                    che = che + 1;
                }
                if (exit == "Y" || exit == "y")
                {
                    che = 0;
                }


            }
        }


    }
}