c# - 在 Windows 窗体应用程序中托管交互式 Web 服务

Question

所以我知道如何在 Windows 窗体应用程序中托管 WCF 服务。但是如何让服务与表单上的控件进行交互。例如，我希望 Web 服务调用将图像加载到图片控件中。如果您找到了这样做的方法，请告诉我。

Answer 1

您可以执行此操作的一种方法如下所示...

注意：我会有点担心这种方法，并且可能想在做这样的事情之前更多地了解你想要实现的目标，但为了在这里回答你的问题，它是......

假设您想允许某人向您发送一张图片以显示在表单上的图片框中，因此从服务开始，它可能如下所示：

[ServiceContract]
public interface IPictureService
{
    [OperationContract]
    void ShowPicture(byte[] picture);
}

[ServiceBehavior(InstanceContextMode = InstanceContextMode.Single)] 
public class PictureService : IPictureService
{
    private readonly Action<Image> _showPicture;

    public PictureService(Action<Image> showPicture)
    {
        _showPicture = showPicture;
    }

    public void ShowPicture(byte[] picture)
    {
        using(var ms = new MemoryStream(picture))
        {
            _showPicture(Image.FromStream(ms));    
        }            
    }
}

现在创建一个用于显示图片的表单（Form1 是表单的名称，pictureBox1 是相关的图片框）。代码如下所示：

public partial class Form1 : Form
{
    private readonly ServiceHost _serviceHost;

    public Form1()
    {
        // Construct the service host using a singleton instance of the
        // PictureService service, passing in a delegate that points to
        // the ShowPicture method defined below
        _serviceHost = new ServiceHost(new PictureService(ShowPicture));
        InitializeComponent();
    }

    // Display the given picture on the form
    internal void ShowPicture(Image picture)
    {
        Invoke(((ThreadStart) (() =>
                                   {
                                       // This code runs on the UI thread
                                       // by virtue of using Invoke
                                       pictureBox1.Image = picture;
                                   })));
    }

    private void Form1_Load(object sender, EventArgs e)
    {
        // Open the WCF service when the form loads
        _serviceHost.Open();
    }

    private void Form1_FormClosing(object sender, FormClosingEventArgs e)
    {
        // Close the WCF service when the form closes
        _serviceHost.Close();
    }
}

为了完整起见，添加一个 app.config 并将其放入（显然，您如何托管服务并不重要，因为 WCF 会在很大程度上将其抽象出来，但我想给您一个完整的工作示例）：

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
  <system.serviceModel>
    <behaviors>
        <serviceBehaviors>
            <behavior name="">
                <serviceMetadata httpGetEnabled="true" />
                <serviceDebug includeExceptionDetailInFaults="false" />
            </behavior>
        </serviceBehaviors>
    </behaviors>
    <services>
        <service name="WindowsFormsApplication1.PictureService">
            <endpoint address="" binding="wsHttpBinding" contract="WindowsFormsApplication1.IPictureService">
                <identity>
                    <dns value="localhost" />
                </identity>
            </endpoint>
            <endpoint address="mex" binding="mexHttpBinding" contract="IMetadataExchange" />
            <host>
                <baseAddresses>
                    <add baseAddress="http://localhost:8732/WindowsFormsApplication1/PictureService/" />
                </baseAddresses>
            </host>
        </service>
    </services>
  </system.serviceModel>
</configuration>

就是这样 - 如果您向 ShowPicture 操作发送一个作为图像的字节数组，它将显示在表单上。

例如，说创建一个控制台应用程序并添加对上面定义的 winforms 应用程序中托管的服务的服务引用，main 方法可以简单地将其包含在其中（并且 logo.png 将显示在表单上）：

var buffer = new byte[1024];
var bytes = new byte[0];
using(var s = File.OpenRead(@"C:\logo.png"))
{
    int read;
    while((read = s.Read(buffer, 0, buffer.Length)) > 0)
    {
        var newBytes = new byte[bytes.Length + read];
        Array.Copy(bytes, newBytes, bytes.Length);
        Array.Copy(buffer, 0, newBytes, bytes.Length, read);
        bytes = newBytes;
    }              
}

var c = new PictureServiceClient();
c.ShowPicture(bytes);