Silverlight从处理程序接收响应
问题描述:
我有一个位于网页上的Silverlight应用程序。它允许用户将多个文档上传到服务器。当我开始上传一个文件到服务器,我会做出一个处理程序的调用一个POST请求,我把它块,如果该文件是太大用下面的代码:Silverlight从处理程序接收响应
private void UploadFileEx()
{
Status = FileUploadStatus.Uploading;
var temp = FileLength - BytesUploaded;
var ub = new UriBuilder(_urlServer);
var complete = temp <= ChunkSize;
ub.Query = string.Format("{3}locationCode={4}&filename={0}&StartByte={1}&Complete={2}", RockDocumentName, BytesUploaded, complete,
string.IsNullOrEmpty(ub.Query) ? string.Empty : string.Format("{0}&", ub.Query.Remove(0, 1)), _locationCode);
var webrequest = (HttpWebRequest) WebRequest.Create(ub.Uri);
webrequest.Method = "POST";
// Begins an asynchronous request for a Stream object to use to write data.
// The asynchronous callback method uses the EndGetRequestStream method to return the actual stream.
// This means
webrequest.BeginGetRequestStream(WriteCallback, webrequest);
}
private void WriteCallback(IAsyncResult asynchronousResult)
{
var webrequest = (HttpWebRequest) asynchronousResult.AsyncState;
// End the operation.
// Here we obtain the stream to write the request
var requestStream = webrequest.EndGetRequestStream(asynchronousResult);
var buffer = new Byte[4096];
int bytesRead;
var tempTotal = 0;
Stream fileStream = File.OpenRead();
fileStream.Position = BytesUploaded;
while ((bytesRead = fileStream.Read(buffer, 0, buffer.Length)) != 0 && tempTotal + bytesRead < ChunkSize)
{
requestStream.Write(buffer, 0, bytesRead);
requestStream.Flush();
BytesUploaded += bytesRead;
tempTotal += bytesRead;
if (UploadProgressChanged != null)
{
var percent = (int) ((BytesUploaded/(double) FileLength)*100);
var args = new UploadProgressChangedEventArgs(percent, bytesRead, BytesUploaded, FileLength,
RockDocumentName);
Dispatcher.BeginInvoke(() => UploadProgressChanged(this, args));
}
}
fileStream.Close();
requestStream.Close();
// Whenever the operation is ready call the ReadCallback method (when this method
// is called we know that the chunk of file has arrived successfully to the server,
// it's time to process the next chunk).
webrequest.BeginGetResponse(ReadCallback, webrequest);
}
我想我的处理程序返回我的文档名称(我为处理程序中的每个文档生成一个新文件名,因为我们有一个正在使用的文档命名标准)。所以,我编写我的AsyncCallback这样,我期待的AsyncState会回到我以为我settting在处理器头:
private void ReadCallback(IAsyncResult asynchronousResult)
{
var documentName = ((System.Net.BrowserHttpWebRequest)asynchronousResult.AsyncState).Headers["documentname"].ToString();
if (BytesUploaded < FileLength)
UploadFileEx();
else
{
Status = FileUploadStatus.Complete;
}
}
这里是我的处理程序:
public void ProcessRequest(HttpContext context) {
Context = context;
UploadFile();
//context.Request.Headers.Add("documentname", "testfilename.pdf");
context.Response.Headers.Add("documentname", "testfilename.pdf");
}
这不是工作正如我原先想的那样。我究竟做错了什么?我是否在我的处理程序中设置了错误标题?我的处理程序是否有另一种方式与Silverlight客户端应用程序交谈?
任何帮助,将不胜感激。提前致谢!
答
如果您的处理程序将文档名称作为Response主体的一部分而不是Header发回,您可能会有更多的运气。
试试这个代码,看看你会得到什么:
private void ReadCallback(IAsyncResult asynchronousResult)
{
var webRequest = (HttpWebRequest) asynchronousResult.AsyncState;
var webResponse = (HttpWebResponse) webRequest.EndGetResponse(asynchronousResult);
var reader = new StreamReader(webResponse.GetResponseStream());
var documentName = reader.ReadToEnd();
reader.Close();
if (BytesUploaded < FileLength)
UploadFileEx();
else
{
DocumentName = documentName;
Status = FileUploadStatus.Complete;
}
}
而在的ProcessRequest:
Context.Response.Write(“Document Name”);
感谢,这工作!从另一天把我的头靠在桌子上,挽救了我。 – Mark 2011-04-18 14:47:58