Silverlight下载网络图片

string fp = Request.QueryString["FilePath"];
            var upfile = new UpLoadFilesBLL().GetupLoadFiles(fp);
            SPSecurity.RunWithElevatedPrivileges(delegate
            {
                string fileName = upfile.FileName + "." + upfile.RootUrl.Split('.')[upfile.RootUrl.Split('.').Length - 1];//客户端保存的文件名
                string filePath = Server.MapPath(upfile.RootUrl); //路径
                //以字符流的形式下载文件
                FileStream fs = new FileStream(filePath,FileMode.Open);
                byte[] bytes = new byte[(int)fs.Length];
                fs.Read(bytes,bytes.Length);
                fs.Close();
                Response.ContentType = "application/octet-stream";
                //通知浏览器下载文件而不是打开
                response.addheader("Content-disposition","attachment;   filename=" + HttpUtility.UrlEncode(fileName,System.Text.Encoding.UTF8));
                Response.BinaryWrite(bytes);
                Response.Flush();
                Response.End();
            });

话说Silverlight做下载的时候是一个很麻烦的事情，刚开始的时候使用WebClient去下载图片，这样只能下载本域下的图片资源，不能跨域。

比如http://www.baidu.com/a.jpg这样的话就会出现安全问题，找了好多资料，都说要搞配置XML什么的，结果试了也不可以，话说也不怎么懂

然后我就想到一个办法，在WebService里面使用WebClient下载图片到本地，然后在Silverlight里面使用FileInfo（“C:\\a.jpg”）这样去找，

可恶的是Silverlight不允许这样获取本地文件。然后就测底无语了。。。

然后使用

WebRequest request = WebRequest.Create(url);
WebResponse response = request.GetResponse();

Stream s=response.GetResponseStream();

这里又报S.leng的异常

//解决401授权不够的问题，下面代码需要添加在GetResponse前面

request.Credentials = System.Net.CredentialCache.DefaultNetworkCredentials;
//request.Credentials = System.Net.CredentialCache.DefaultCredentials;

最后东找西找，终于找到了解决这个异常的问题

下面是代码

Webservice里面的方法 (例如url=http://baidu.com/a.jpg)

[WebMethod]
        //根据网络地址，下载图片
        public byte[] DownLoadImage(string url)
        {
            WebRequest request = WebRequest.Create(url);
            WebResponse response = request.GetResponse();
            BinaryReader rsReader = new BinaryReader(response.GetResponseStream());
            byte[] buff = rsReader.ReadBytes((int)response.ContentLength);
            rsReader.Read(buff,buff.Length);
            rsReader.Close();
            response.Close();
            return buff;
        }

然后在Silverlight里面调用

MasterDataServiceSoapClient service = new      MasterDataServiceSoapClient（）；

                service.DownLoadImageAsync(this.txbaddress.Text);
                service.DownLoadImageCompleted += new EventHandler<DownLoadImageCompletedEventArgs>(service_DownLoadImageCompleted);

void service_DownLoadImageCompleted(object sender,DownLoadImageCompletedEventArgs e)
        {
            if (e.Result.Length==0)
            {
                this.txbMessage.Text = "网络故障，下载失败！";
                this.txbaddress.IsEnabled = true;
            }
            else {
                //FileInfo mapInfo = new FileInfo(e.Result);
                //string[] mapFullName = mapInfo.Name.Split('.');

                //if (!(mapFullName[mapFullName.Length - 1].Contains("jpg")))
                //{
                //    MsgBox.Show("图片不是jpg格式！","消息提示",MsgBoxButton.OKCancel,Msginfo.Error);
                //    return;
                //}

                //FileStream inputStream = mapInfo.OpenRead();
                //int readSize = 204800;
                //if (inputStream.Length > readSize)
                //{
                //    MsgBox.Show("图片大小不能超过200KB！",Msginfo.Error);
                //    return;
                //}

                //byte[] imageb = new byte[inputStream.Length];
                //inputStream.Read(imageb,imageb.Length);
                //inputStream.Close();
                this.FrmCustomerManager.upload_UploadComplete(e.Result);
                this.DialogResult = false;
            }

void service_DownLoadImageCompleted(object sender,imageb.Length);
                //inputStream.Close();
                this.FrmCustomerManager.upload_UploadComplete(e.Result);
                this.DialogResult = false;
            }

e.result返回的是一个字节数组byte[]..

uploadcomplete这里不用管，里面我写的是把字节数组e.result转换成了一个burshimage 也就是一个背景图片类型给了一个Stackpanel的bg

下面是如何把字节数组转换城图片的代码

public ImageBrush ConverterImageBrush(byte[] Image)
        {
            //MemoryStream inputStream = new MemoryStream(Image,true);
            //inputStream.Write(Image,Image.Length);
            System.IO.Stream inputStream = new System.IO.MemoryStream(Image);
            System.Windows.Media.Imaging.BitmapImage image = new System.Windows.Media.Imaging.BitmapImage();
            image.SetSource(inputStream);
            return new ImageBrush() { ImageSource = image,Stretch = Stretch.Uniform };
        }

好了就这么多

Silverlight下载网络图片

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