Silverlight 4 RC文件上传与上传进度：如何？

据说Silverlight 4 RC的一个新功能是它现在支持上传进度.

我假设这意味着可以在没有“分块”的情况下制作上传文件进度条,但我无法弄清楚如何做到这一点,那么我们该如何做呢？源代码示例会很棒.

谢谢！

解决方法

好吧,经过大量的游戏,我已经弄明白了：

private void UploadFile(string url,CustomPostDataInfo pdi)
    {

        // Use the client http stack!

        //HttpWebRequest webRequest = (HttpWebRequest)WebRequest.Create(url);
        HttpWebRequest webRequest = (HttpWebRequest)WebRequestCreator.ClientHttp.Create(new Uri(url));

        webRequest.AllowWriteStreamBuffering = false; // <-- this enables upload progress reporting!

        webRequest.Method = "POST";
        webRequest.ContentType = "multipart/form-data; boundary=" + pdi.Boundary; // Boundary only needed for multipart form ada

        // Calculate our response length
        webRequest.ContentLength = pdi.FormDataHeader.Length + pdi.File2Upload.Length + pdi.FormDataFooter.Length; // Calculate the length of your entire message here,required

        pdi.request = webRequest;

        webRequest.BeginGetRequestStream(new AsyncCallback(WritetoStreamCallback),pdi);
    }

    private void WritetoStreamCallback(IAsyncResult asynchronousResult)
    {
        CustomPostDataInfo pdi = (AmazonS3PostDataInfo)asynchronousResult.AsyncState;
        HttpWebRequest webRequest = pdi.request;
        Stream requestStream = webRequest.EndGetRequestStream(asynchronousResult);
        UTF8Encoding encoding = new UTF8Encoding();

        UpdateShowProgress(false,"Uploading file..."); // Your custom update event - make sure to use a dispatcher to update on the UI thread as this is running on a separate thread.

        // Write any pre file data if needed
        // ...

        // Write our file data
        {
            // Read chunks of this file
            byte[] buffer = new Byte[1024 * 32];
            Stream fileStream = pdi.File2Upload.OpenRead();
            int bytesRead = 0;
            while ((bytesRead = fileStream.Read(buffer,buffer.Length)) != 0)
            {
                requestStream.Write(buffer,bytesRead);
                requestStream.Flush(); // Will block until data is sent

                bytesuploaded += bytesRead;

                //Show the progress change
                UpdateShowProgress(false,"Uploading file...");
            }
        }

        // Write any post file data
        // ...

        UpdateShowProgress(false,"Uploaded,waiting for response...");

        requestStream.Close();

        // Get the response from the HttpHandler
        webRequest.BeginGetResponse(new AsyncCallback(ReadHttpResponseCallback),webRequest);

    }

    private void ReadHttpResponseCallback(IAsyncResult asynchronousResult)
    {
        HttpWebRequest webRequest = (HttpWebRequest)asynchronousResult.AsyncState;
        HttpWebResponse webResponse = (HttpWebResponse)webRequest.EndGetResponse(asynchronousResult);
        StreamReader reader = new StreamReader(webResponse.GetResponseStream());

        string response = reader.ReadToEnd(); // Get the result

        reader.Close();

        UpdateShowProgress(true,response);
    }