Silverlight 4 RC 文件上传和上传进度:如何? [英] Silverlight 4 RC File Upload with Upload Progress: how to?

问题描述

据说 Silverlight 4 RC 的新功能之一是它现在支持上传进度.

It's been stated that one of the new features of Silverlight 4 RC is that it now supports upload progress.

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，但我不知道如何做到这一点，那么我们该怎么做呢?源代码示例会很棒.

I'm assuming this means it's possible to make an upload file progress bar without "chunking" but I can't figure out how to do this, so how do we do this? Source code examples would be great.

谢谢！

推荐答案

好了，玩了好久终于明白了:

Ok, after lots of playing I've got it figured out:

   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, 0, buffer.Length)) != 0)
            {
                requestStream.Write(buffer, 0, 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);
    }

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