Question

我有以下代码可以很好地通过FTP发送文件，但它会阻止我的UI。

 FtpWebRequest request = (FtpWebRequest)WebRequest.Create(ftpUrl + filename);
            request.UsePassive = false;
            request.Method = WebRequestMethods.Ftp.UploadFile;
            request.Credentials = new NetworkCredential(ftpUser, ftpPass);
            request.Timeout = 10000; //10 second timeout

            byte[] fileContents = File.ReadAllBytes(fullPath);
            request.ContentLength = fileContents.Length;
            //Stream requestStream = await request.GetRequestStreamAsync();
            Stream requestStream = request.GetRequestStream();
            requestStream.Write(fileContents, 0, fileContents.Length);

            requestStream.Close();

我想将Stream切换到注释行，以便我异步调用并且不阻塞我的UI，并且它工作正常，除了超时（根据文档，该超时仅用于同步使用）。

问题是如何使异步调用超时？

Answer 1

从文档FtpWebRequest.Timeout Property中，超时是用GetResponse方法发出的同步请求等待响应以及GetRequestStream方法等待流的毫秒数。因此，不再有API可以异步使用它。

也许这是实现它的一种好方法。将 FtpWebRequest 代码放入Task中进行尝试。

// Start a new task (this launches a new thread)
Task.Factory.StartNew (() => {
    // Do some work on a background thread, allowing the UI to remain responsive
    DoSomething();
// When the background work is done, continue with this code block
}).ContinueWith (task => {
    DoSomethingOnTheUIThread();
// the following forces the code in the ContinueWith block to be run on the
// calling thread, often the Main/UI thread.
}, TaskScheduler.FromCurrentSynchronizationContext ());

如何将超时添加到异步FtpWebRequest

1 个答案: