C# Creat Write Read File

class Program
{

    static void Main(string[] args)
    {

        string dir = "c:\\";

        //設定資料夾路徑

        string folder = "myFolder";

        //設定資料夾名稱

        string file = "mytext.txt";

        //設定檔案名稱

        string path = System.IO.Path.Combine(dir,folder);

        //路徑加入資料夾名稱

        if (!System.IO.Directory.Exists(path))

        {

            //判斷資料夾是否存在

            System.IO.Directory.CreateDirectory(path);

            //建立資料夾

            System.Console.WriteLine("CreateDirectory Success");

        }

        path = System.IO.Path.Combine(path,file);

        //路徑加入檔案名稱

        if (!System.IO.File.Exists(path))

        {

            //判斷檔案是否存在

            using (StreamWriter sw = System.IO.File.CreateText(path))

            {

                //新增檔案並寫入資料

                sw.Write("hello", Encoding.UTF8);

                sw.Close();

            }

            System.Console.WriteLine("CreateFile Success");

        }

        else

        {

            using (StreamReader sr = System.IO.File.OpenText(path))

            {

                //開啟檔案並讀取資料

                System.Console.WriteLine(sr.ReadToEnd());

                sr.Close();

            }

        }

    Console.ReadKey();

    }

}

C# Send Mail (SmtpClient)

class Program
{
    
    static void Main(string[] args)

    {

        try

        {

            SmtpClient mySmtp = new SmtpClient("stmp host",smtp port);

            //定義smtp的連接(smtp 網址,smtp port(預設25))

            mySmtp.Credentials = new System.Net.NetworkCredential("account", "password");

            //設定寄件者的認證(帳號,密碼)

            MailMessage msgMail = new MailMessage();

            //定義電子郵件

            msgMail.From = new MailAddress("account@smtp host");

            //寄件者

            msgMail.To.Add("account@smtp host");

            //收件者

            msgMail.Subject = "mail subject";

            //主旨

            msgMail.SubjectEncoding = System.Text.Encoding.UTF8;

            //主旨的編碼

            msgMail.IsBodyHtml = true;

            //設定郵件內容採用HTML格式

            msgMail.Body = "mail content";

            //設定郵件內容

            msgMail.BodyEncoding = Encoding.UTF8;

            //內容編碼               

            mySmtp.Send(msgMail);

            //發送mail

            Console.WriteLine("send success");

        }

        catch (Exception e)

        {

            Console.WriteLine(e.ToString());

        }

        Console.ReadKey();

    }

}

C# Socket Sample(Client-server)

Server 端：

namespace lf.socket.clientserver
{

    class Server

    {

        static void Main(string[] args)

        {

            IPEndPoint ipont = new IPEndPoint(IPAddress.Any, 20);

            //將IP位址和Port宣告為服務的連接點(所有網路介面卡 IP,20 Port)

            Socket newsock = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);

            //宣告一個Socket通訊介面(使用IPv4協定,通訊類型,通訊協定)

            newsock.Bind(ipont);

            //建立本機連線   

            newsock.Listen(10);

            //偵測連接(最大連接數)

            while (true)

            { 

                Socket client = newsock.Accept();

                //宣告一個Socket等於新建立的連線

                IPEndPoint clientip = (IPEndPoint)client.RemoteEndPoint;

                //宣告一個連接點為socket端的連接點

                System.Console.WriteLine("Client End Point = " + clientip);

                //印出遠端IP位址

                SocketListener listener = new SocketListener(client);

                //宣告一個監聽類別SocketListener監聽client訊息

                Thread thread = new Thread(new ThreadStart(listener.run));

                //宣告一個執行序去跑SocketListener監聽事件

                thread.Start();           

            }

        }

    }



    public class SocketListener

    {

        private Socket socket;

        public SocketListener(Socket socket)

        {

            this.socket = socket;

            //建構元取得遠端socket連線

        }

        public void run()

        {

            while (true)

            {

                byte[] data = new byte[1024];

                //定義一個資料緩衝區接收長度最大為(1024)

                int len = socket.Receive(data);

                //接收資料至緩衝區中並回傳成功街收位元數

                if (len == 0) break;

                //若成功接收位元數為0則跳出迴圈

                System.Console.WriteLine(Encoding.UTF8.GetString(data,0,len));

                //印出編碼後的資料(資料,起始位置,長度)

            }

            socket.Close();

        }

    }

}

Client 端：

namespace lf.socket.clientserver

{

    class Client

    { 

        static void Main(string[] args)

        {

            IPEndPoint ipont = new IPEndPoint(IPAddress.Parse("127.0.0.1"), 20);

            //將IP位址和Port宣告為服務的連接點(Server Ip,20 Port)

            Socket server = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);

            //宣告一個Socket通訊介面(使用IPv4協定,通訊類型,通訊協定)

            server.Connect(ipont);

            //建立至遠端主機的連接

            while (true)

            {

                string input = Console.ReadLine();

                //接收輸入字串

                if (input == "exit")break;

                //若輸入exit則跳出迴圈

                byte[] data = Encoding.UTF8.GetBytes(input);

                //將字串以UTF8編碼存入緩衝區

                server.Send(data);

            }

            server.Shutdown(SocketShutdown.Both);

            //關閉遠端的傳送與接收

            server.Close();

            //關閉連接

            System.Console.Write("Disconnecting from server...");

            System.Console.ReadKey();

        }

    }

}