从OperationContract方法返回图像(WCF服务)

Question

我试图从WCF服务获取一个Image
我有一个OperationContract函数,它返回一个Image到客户端,
但是当我从客户端调用它时,我得到这个异常: The socket connection was aborted. This could be caused by an error processing your message or a receive timeout being exceeded by the remote host, or an underlying network resource issue. Local socket timeout was '00:00:59.9619978'.

客户:

private void btnNew_Click(object sender, EventArgs e)
    {
        picBox.Picture = client.GetScreenShot();
    }

Service.cs:

public Image GetScreenShot()
    {
        Rectangle bounds = Screen.GetBounds(Point.Empty);
        using (Bitmap bmp = new Bitmap(bounds.Width,bounds.Height))
        {
            using (Graphics g = Graphics.FromImage(bmp))
            {
                g.CopyFromScreen(Point.Empty, Point.Empty, bounds.Size);
            }
            using (MemoryStream ms = new MemoryStream())
            {
                bmp.Save(ms, System.Drawing.Imaging.ImageFormat.Png);
                return Image.FromStream(ms);
            }
        }
    }

IScreenShot界面:

    [ServiceContract]
public interface IScreenShot
{
    [OperationContract]
    System.Drawing.Image GetScreenShot();
}

那么为什么会发生这种情况,我该如何解决呢？

Answer 1

我已经明白了.

• 首先使用TransferMode.Streamed //或StreamedResponse取决于您的需要.
• 返回流,不要忘记设置Stream.Postion = 0所以从开始读取流.

在服务中:

    public Stream GetStream()
    {
        Rectangle bounds = Screen.GetBounds(Point.Empty);
        using (Bitmap bmp = new Bitmap(bounds.Width, bounds.Height))
        {
            using (Graphics g = Graphics.FromImage(bmp))
            {
                g.CopyFromScreen(Point.Empty, Point.Empty, bounds.Size);
            }
            MemoryStream ms = new MemoryStream();
            bmp.Save(ms, System.Drawing.Imaging.ImageFormat.Jpeg);
            ms.Position = 0;  //This's a very important
            return ms;
        }
    }

界面:

[ServiceContract]
public interface IScreenShot
{
    [OperationContract]
    Stream GetStream();
}

在客户端:

public partial class ScreenImage : Form
{
    ScreenShotClient client;
    public ScreenImage(string baseAddress)
    {
        InitializeComponent();
        NetTcpBinding binding = new NetTcpBinding(SecurityMode.None);
        binding.TransferMode = TransferMode.StreamedResponse;
        binding.MaxReceivedMessageSize = 1024 * 1024 * 2;
        client = new ScreenShotClient(binding, new EndpointAddress(baseAddress));
    }

    private void btnNew_Click(object sender, EventArgs e)
    {
        picBox.Image = Image.FromStream(client.GetStream());
    }
}