在 前面几篇文章中，分别就WCF如何与Ajax交互，如何返回json数据给Ajax，如何为ExtJs控件提供数据，如何用Http的访问方式异步调用 Restful的WCF服务，本文着重讲述如何用Restful方式调用WCFl进行文件的上传和下载。在前面的文章中，曾经写过Restful的WCF 支持两种格式的请求和响应的数据格式：1）XML 2) JSON。事实上WCF不光支持上述两种格式，它还支持原生数据(Raw,来源于Carlos' blog)。 这样一来，WCF的Restful方式实际上支持任意一种格式的，因为原生的即表明可以是任意一种格式，WCF从客户端到服务端，从服务端到客户端都会保 持这种数据的原来的数据格式。通过查阅MSDN中WebMessageEncodingBindingElement 类的说明：也能找到上述的论证
首 先总结一下如何在Restful的WCF的服务端和客户端传递原生的数据(Raw),在WCF中，返回值或者参数为System.IO.Stream或者 System.IO.Stream的派生类型的时候，加配上HTTP请求和Restful服务操作响应消息中的ContentType，便能实现原生数据 的传输。
下面通过一个上传和下载图片文件的项目示例来演示如上的结论。
第一步：在VS2008中，创建一个解决方案：WcfBinaryRestful，包括四个项目：如下图所示：
| 项目名称 | 说明 |
| WcfBinaryRestful.Contracts | WCF服务的契约部分 |
| WcfBinaryRestful.Service | WCF服务具体实现部分 |
| WcfBinaryRestful.Host | WCF服务的Console程序的承载程序 |
| WcfBinaryRestful.Client | 客户端 |
第二步：在WcfBinaryRestful.Contracts中创建并设计服务契约IService.cs,代码如下：
using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.ServiceModel;namespace WcfBinaryRestful.Contracts{
[ServiceContract] public interface IService
{ [OperationContract] System.IO.Stream ReadImg(); [OperationContract] void ReceiveImg(System.IO.Stream stream); 
}
}
其中ReadImg方法用于提供jpg图片文件，供客户端下载，而ReceiveImg用于接收客户端上传的jpg图片
第三步：在WcfBinaryRestful.Service项目中创建并设计服务具体实现类:Service.cs
using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.ServiceModel.Web;using System.Drawing;using System.Diagnostics;namespace WcfBinaryRestful.Service{ public class Service : Contracts.IService { [WebInvoke(Method = "*", UriTemplate = "ReadImg")] public System.IO.Stream ReadImg() { string runDir = System.Environment.CurrentDirectory; string imgFilePath = System.IO.Path.Combine(runDir, "jillzhanglogo.jpg"); System.IO.FileStream fs = new System.IO.FileStream(imgFilePath, System.IO.FileMode.Open); System.Threading.Thread.Sleep(2000); WebOperationContext.Current.OutgoingResponse.ContentType = "image/jpeg"; return fs; } [WebInvoke(Method = "*", UriTemplate = "ReceiveImg")] public void ReceiveImg(System.IO.Stream stream) { Debug.WriteLine(WebOperationContext.Current.IncomingRequest.ContentType); System.Threading.Thread.Sleep(3000); string runDir = System.Environment.CurrentDirectory; string imgFilePath = System.IO.Path.Combine(runDir, "ReceiveImg.jpg"); Image bmp = Bitmap.FromStream(stream); bmp.Save(imgFilePath); } }}
第四步：用配置的方式，创建服务承载项目：WcfBinaryRestful.Host。并使得服务可以用Restful方式访问。
Host.cs
using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.ServiceModel;namespace WcfBinaryRestful.Host{ public class Host { static void Main() { using (ServiceHost host = new ServiceHost(typeof(Service.Service))) { host.Open(); Console.WriteLine("服务已经启动！"); Console.Read(); } } }}
App.config
<?xml version="1.0" encoding="utf-8" ?><configuration> <system.serviceModel> <services> <service name="WcfBinaryRestful.Service.Service"> <host> <baseAddresses> <add baseAddress="http://127.0.0.1:9874/"/> </baseAddresses> </host> <endpoint address="" binding="webHttpBinding" contract="WcfBinaryRestful.Contracts.IService" behaviorConfiguration="WcfBinaryRestfulBehavior"></endpoint> </service> </services> <behaviors> <endpointBehaviors> <behavior name="WcfBinaryRestfulBehavior"> <webHttp/> </behavior> </endpointBehaviors> </behaviors> </system.serviceModel></configuration>
第五步：实现客户端程序
Form1.cs
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;namespace WcfBinaryRestful.Client{ public partial class Form1 : Form { public Form1() { InitializeComponent(); } System.Net.WebClient wc; private void button1_Click(object sender, EventArgs e) { wc = new System.Net.WebClient(); SaveFileDialog op = new SaveFileDialog(); if (op.ShowDialog() == DialogResult.OK) { wc.DownloadFileAsync(new Uri("http://127.0.0.1:9874/ReadImg"), op.FileName); wc.DownloadFileCompleted += new AsyncCompletedEventHandler(wc_DownloadFileCompleted); button2.Enabled = true; button1.Enabled = false; } } void wc_DownloadFileCompleted(object sender, AsyncCompletedEventArgs e) { if (e.Cancelled) { button2.Enabled = false; button1.Enabled = true; MessageBox.Show("用户已经取消下载！"); return; } using (System.Net.WebClient wc = e.UserState as System.Net.WebClient) { button2.Enabled = false; button1.Enabled = true; MessageBox.Show("下载完毕!"); } } private void button2_Click(object sender, EventArgs e) { if (wc != null) { wc.CancelAsync(); } } System.Net.WebClient uploadWc = new System.Net.WebClient(); private void button3_Click(object sender, EventArgs e) { OpenFileDialog op = new OpenFileDialog(); op.Filter = "jpg文件(*.jpg)|*.jpg"; if (op.ShowDialog() == DialogResult.OK) { uploadWc.Headers.Add("Content-Type", "image/jpeg"); System.IO.FileStream fs = new System.IO.FileStream(op.FileName,System.IO.FileMode.Open); byte[] buffer = new byte[(int)fs.Length]; fs.Read(buffer, 0, (int)fs.Length); fs.Close(); uploadWc.UploadDataCompleted += new System.Net.UploadDataCompletedEventHandler(uploadWc_UploadDataCompleted); uploadWc.UploadDataAsync(new Uri("http://127.0.0.1:9874/ReceiveImg"), buffer); button3.Enabled = false; button4.Enabled = true; } } void uploadWc_UploadDataCompleted(object sender, System.Net.UploadDataCompletedEventArgs e) { if (e.Cancelled) { button3.Enabled = true; button4.Enabled = false; MessageBox.Show("用户已经取消上传！"); return; } MessageBox.Show("完成上传！"); button3.Enabled = true; button4.Enabled = false; } private void button4_Click(object sender, EventArgs e) { uploadWc.CancelAsync(); } }}
设置好多启动项目调试后，调试，出现如下的运行界面：
1.服务承载程序运行界面图：
2.客户端运行界面图：
点击开始下载按钮，选择一个下载文件的保存位置，等待一会后，会提示下载成功，如下图所示：
打开刚才选择下载文件的保存位置，便能发现已经成功下载了jpg的图片文件：
当然顺便还可以温习一下如何异步调用Restful的WCF服务，点击取消下载可以停止下载，不再多说
点击开始上传，选择一个要上传的jpg图片，等待几秒钟，便能收到上传成功的对话框，如下图所示：
找到服务承载程序所在目录，便能看到上传的jpg图像文件：
