使用 C# 通過 sockets 發送和接收圖像

Question

我正在嘗試在 C# 中設置兩個程序。基本上，設置一個簡單的客戶端服務器，我希望服務器在其中偵聽來自客戶端的圖像。 然后，在收到圖像后，將其顯示在 PictureBox 中。

我一直遇到以下錯誤：

System.Drawing.dll 中發生類型為“System.ArgumentException”的第一次機會異常

錯誤發生在偵聽此行的服務器代碼上：Image bmp = Image.FromStream(ms); 有任何想法嗎？

監聽的服務器代碼：

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.IO;
using System.Net;
using System.Net.Sockets;

namespace NetView
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
            startListening();
        }

        private void startListening()
        {
            ////////////////////////////////////////////

            Console.WriteLine("Server is starting...");
            byte[] data = new byte[1024];
            IPEndPoint ipep = new IPEndPoint(IPAddress.Any, 9050);

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

            newsock.Bind(ipep);
            newsock.Listen(10);
            Console.WriteLine("Waiting for a client...");

            Socket client = newsock.Accept();
            IPEndPoint newclient = (IPEndPoint)client.RemoteEndPoint;
            Console.WriteLine("Connected with {0} at port {1}",
                            newclient.Address, newclient.Port);

            while (true)
            {
                data = ReceiveVarData(client);
                MemoryStream ms = new MemoryStream(data);
                try
                {
                    Image bmp = Image.FromStream(ms);
                    pictureBox1.Image = bmp;
                }
                catch (ArgumentException e)
                {
                    Console.WriteLine("something broke");
                }


                if (data.Length == 0)
                    newsock.Listen(10);
            }
            //Console.WriteLine("Disconnected from {0}", newclient.Address);
            client.Close();
            newsock.Close();
            /////////////////////////////////////////////

        }

        private static byte[] ReceiveVarData(Socket s)
        {
            int total = 0;
            int recv;
            byte[] datasize = new byte[4];

            recv = s.Receive(datasize, 0, 4, 0);
            int size = BitConverter.ToInt32(datasize, 0);
            int dataleft = size;
            byte[] data = new byte[size];


            while (total < size)
            {
                recv = s.Receive(data, total, dataleft, 0);
                if (recv == 0)
                {
                    break;
                }
                total += recv;
                dataleft -= recv;
            }
            return data;
        }

        private void Form1_Load(object sender, EventArgs e)
        {

        }

    }
}

客戶端代碼：

using System;
using System.Net;
using System.Net.Sockets;
using System.Text;
using System.Drawing;
using System.IO;

namespace ConsoleApplication2
{
    class Program
    {
        static void Main(string[] args)
        {
            byte[] data = new byte[1024];
            int sent;
            IPEndPoint ipep = new IPEndPoint(IPAddress.Parse("127.0.0.1"), 9050);

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

            try
            {
                server.Connect(ipep);
            }
            catch (SocketException e)
            {
                Console.WriteLine("Unable to connect to server.");
                Console.WriteLine(e.ToString());
                Console.ReadLine();
            }


            Bitmap bmp = new Bitmap("c:\\eek256.jpg");

            MemoryStream ms = new MemoryStream();
            // Save to memory using the Jpeg format
            bmp.Save(ms, System.Drawing.Imaging.ImageFormat.Jpeg);

            // read to end
            byte[] bmpBytes = ms.GetBuffer();
            bmp.Dispose();
            ms.Close();

            sent = SendVarData(server, bmpBytes);

            Console.WriteLine("Disconnecting from server...");
            server.Shutdown(SocketShutdown.Both);
            server.Close();
            Console.ReadLine();
        }

        private static int SendVarData(Socket s, byte[] data)
        {
            int total = 0;
            int size = data.Length;
            int dataleft = size;
            int sent;

            byte[] datasize = new byte[4];
            datasize = BitConverter.GetBytes(size);
            sent = s.Send(datasize);

            while (total < size)
            {
                sent = s.Send(data, total, dataleft, SocketFlags.None);
                total += sent;
                dataleft -= sent;
            }
            return total;
        }
    }
}

Answer 1

ArgumentException告訴您流中的圖像格式無效。 這可能是由客戶端應用程序在發送數據之前關閉內存流引起的。

嘗試替換byte[] bmpBytes = ms.GetBuffer(); 同

byte[] bmpBytes = ms.ToArray();

或者在發送數據后關閉流。

請記住， .GetBuffer()返回的字節數組返回基礎數組，而不是它的副本（ .ToArray()返回副本），只要父流有效。

Answer 2

如果您可以訪問JPG文件本身（如示例中所示），則應發送文件字節而不使用Image / Bitmap類。 通過讀取JPG文件並重新編碼為JPG，您將降低圖像質量並產生不必要的開銷。 如果內存空間有限，您可以使用File.ReadAllBytes()快速獲取完整的byte[]或讀取/發送它。

Answer 3

發送圖像的更好方法是使用BinaryFormatter。

例如，我自己的代碼中的一些片段每秒發送一個圖像...

發送：

        TcpClient client = new TcpClient();  
        try  
        {    
            client.Connect(address, port); 

            // Retrieve the network stream.  
            NetworkStream stream = client.GetStream();  
            MessageData data = new MessageData(imageToSend); 

            IFormatter formatter = new BinaryFormatter();

            while(true)
            {
                formatter.Serialize(stream, data);
                Thread.Sleep(1000);
                data.GetNewImage();
            }    
        } 

接收：

        TcpListener listener = new TcpListener(address, port);
        listener.Start();

        try
        { 
            using (TcpClient client = listener.AcceptTcpClient())
            {
                stream = client.GetStream();

                IFormatter formatter = new BinaryFormatter();
                while (true)
                {
                    MessageData data = (MessageData)formatter.Deserialize(stream);

                    if (ImageReceivedEvent != null) ImageReceivedEvent(data.Picture);
                }
            }
        }

MessageData類只保存圖像並具有[Serializable]屬性。

Answer 4

使用Arul的代碼來正確發送數據 - 你想要.ToArray（），而不是.GetBuffer（）。 然后，您將要在后台線程上運行服務器的'startListening'方法，否則您實際上看不到任何內容（因為表單線程將忙於運行服務器代碼。請嘗試：

var t = new Thread(startListening);
t.IsBackground = true;
t.start();

在Form_Load方法中，而不是在構造函數中直接調用startListening。

Answer 5

這是一個適合我的代碼。 用戶通過按鈕啟動服務器，客戶端通過打開計算機的文件對話框選擇照片。 最后發送圖像但要注意照片大小，因為UDP無法傳輸大量數據。

服務器：

    delegate void showMessageInThread(string message);
    UdpClient listener = null;
    IPEndPoint endpoint = null;
    Thread listenThread = null;

    public Form1()
    {
        InitializeComponent();
    }

    private void Form1_Load(object sender, EventArgs e)
    {

    }

    private void button1_Click(object sender, EventArgs e)
    {
        startServer();
    }
    private void startServer()
    {
        endpoint = new IPEndPoint(IPAddress.Any, 1234);
        listener = new UdpClient(endpoint);
        ShowMsg("Waiting for a client!");

        listenThread = new Thread(new ThreadStart(Listening));
        listenThread.Start();
    }
    private void Listening()
    {
        while (true)
        {
            //take the coming data
            byte[] comingDataFromClient = listener.Receive(ref endpoint);
            ImageConverter convertData = new ImageConverter();
            Image image =  (Image)convertData.ConvertFrom(comingDataFromClient);
            pictureBox1.Image = image;
        }
   private void ShowMsg(string msg)
   {
      this.richTextBox1.Text += msg + "\r\n";
   }

客戶：

   Socket server = null;
    MemoryStream ms;
    IPEndPoint endpoint = null;
    public Form1()
    {
        InitializeComponent();
    }
    private void Form1_Load(object sender, EventArgs e)
    {
        server = new Socket(AddressFamily.InterNetwork,
            SocketType.Dgram, ProtocolType.Udp);
        endpoint = new IPEndPoint(IPAddress.Parse("127.0.0.1"), 1234);
    }
    private void btn_browse_Click(object sender, EventArgs e)
    {
        openFileDialog1.ShowDialog();
        string path = openFileDialog1.FileName;
        pictureBox1.Image = Image.FromFile(path);
        textPath.Text = path;
    }
    private void btn_send_Click(object sender, EventArgs e)
    {
        try
        {                
            ms = new MemoryStream();
            Bitmap bmp = new Bitmap(this.openFileDialog1.FileName);
            bmp.Save(ms, ImageFormat.Jpeg);
            byte[] byteArray = ms.ToArray();

            server.Connect(endpoint);
            server.SendTo(byteArray, endpoint);

            }
        }
        catch (Exception ex)
        {

        }

Answer 6

data = ReceiveVarData(client);
MemoryStream ms = new MemoryStream(data);
Image bmp = Image.FromStream(ms);
pictureBox1.Image = bmp;

該錯誤可能是由於 MemoryStream 中收到的損壞或不完整的 bmp 圖像造成的，它在增加套接字發送/接收緩沖區值后對我來說工作正常
將發送方“Socket.SendBufferSize”和接收方“Socket.ReceiveBufferSize”調整為較大的值，例如 = 1024 * 2048 *10 這將有助於一次發送整個圖像。 或者另一種解決方案是在形成接收圖像的代碼行之前檢查接收到的數據大小（data.length）是否與發送的圖像數據大小相同 stream