从FTP下载具有进度的文件 - TotalBytesToReceive总是-1？

本文介绍了从FTP下载具有进度的文件 - TotalBytesToReceive总是-1？的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述 29岁程序员，3月因学历无情被辞！ 文件正在下载，并且ProgressChanged事件正在调用，除了事件参数TotalBytesToReceive始终为-1。 TotalBytes增加了，但是我无法计算没有总数的百分比。 我想我可以通过其他ftp命令找到文件大小，但是我想知道为什么这样做不能实现， 我的代码： FTPClient request = new FTPClient （）; request.Credentials = credentials; request.DownloadProgressChanged + = new DownloadProgressChangedEventHandler（request_DownloadProgressChanged）; //request.DownloadDataCompleted + = new DownloadDataCompletedEventHandler（request_DownloadDataCompleted）; request.DownloadDataAsync（new Uri（folder + file））; while（request.IsBusy）; .... static void request_DownloadProgressChanged（object sender，DownloadProgressChangedEventArgs e） { if（e.TotalBytesToReceive == -1） { l.reportProgress（ - 1，FormatBytes（e.BytesReceived）+out of？）; } else { l.reportProgress（e.ProgressPercentage，Downloaded+ FormatBytes（e.BytesReceived）+out of+ FormatBytes（e.TotalBytesToReceive）+ （+ e.ProgressPercentage +％））; } } .... class FTPClient：WebClient {保护覆盖WebRequest GetWebRequest（System.Uri地址） { FtpWebRequest req =（FtpWebRequest）base.GetWebRequest（address）; req.UsePassive = false; return req; $ / code $ / pre $ b $ p感谢。 解决方案所以我有同样的问题。我通过首先检索文件大小来解决它。 //获取用于与服务器通信的对象。 FtpWebRequest请求=（FtpWebRequest）WebRequest.Create（URL）; request.Method = WebRequestMethods.Ftp.GetFileSize; request.Credentials = networkCredential; FtpWebResponse response =（FtpWebResponse）request.GetResponse（）; Stream responseStream = response.GetResponseStream（）; bytes_total = response.ContentLength; //这是一个int成员变量，用于以后存储 Console.WriteLine（Fetch Complete，ContentLength {0}，response.ContentLength）; response.Close（）; webClient = new MyWebClient（）; webClient.Credentials = networkCredential; ; webClient.DownloadDataCompleted + = new DownloadDataCompletedEventHandler（FTPDownloadCompleted）; webClient.DownloadProgressChanged + = new DownloadProgressChangedEventHandler（FTPDownloadProgressChanged）; webClient.DownloadDataAsync（new Uri（URL））; 然后在回调中进行数学运算。 private void FTPDownloadProgressChanged（object sender，DownloadProgressChangedEventArgs e） { progressBar.Value =（int）（（（float）e.BytesReceived /（float）bytes_total ）* 100.0）; } I am trying to download a file from an FTP server with a progress bar.The file is downloading, and the ProgressChanged event is calling, except in the event args TotalBytesToReceive is always -1. TotalBytes increases, but I am unable to calculate the percentage without the total.I imagine I could find the file size through other ftp commands, but I wonder why this doesn't work?My code:FTPClient request = new FTPClient();request.Credentials = credentials;request.DownloadProgressChanged += new DownloadProgressChangedEventHandler(request_DownloadProgressChanged);//request.DownloadDataCompleted += new DownloadDataCompletedEventHandler(request_DownloadDataCompleted);request.DownloadDataAsync(new Uri(folder + file));while (request.IsBusy) ;....static void request_DownloadProgressChanged(object sender, DownloadProgressChangedEventArgs e){ if (e.TotalBytesToReceive == -1) { l.reportProgress(-1, FormatBytes(e.BytesReceived) + " out of ?" ); } else { l.reportProgress(e.ProgressPercentage, "Downloaded " + FormatBytes(e.BytesReceived) + " out of " + FormatBytes(e.TotalBytesToReceive) + " (" + e.ProgressPercentage + "%)"); }}....class FTPClient : WebClient{ protected override WebRequest GetWebRequest(System.Uri address) { FtpWebRequest req = (FtpWebRequest)base.GetWebRequest(address); req.UsePassive = false; return req; }}Thanks. 解决方案 So I had the same issue. I got around it by retrieving the file size first. // Get the object used to communicate with the server. FtpWebRequest request = (FtpWebRequest)WebRequest.Create("URL"); request.Method = WebRequestMethods.Ftp.GetFileSize; request.Credentials = networkCredential; FtpWebResponse response = (FtpWebResponse)request.GetResponse(); Stream responseStream = response.GetResponseStream(); bytes_total = response.ContentLength; //this is an int member variable stored for later Console.WriteLine("Fetch Complete, ContentLength {0}", response.ContentLength); response.Close(); webClient = new MyWebClient(); webClient.Credentials = networkCredential; ; webClient.DownloadDataCompleted += new DownloadDataCompletedEventHandler(FTPDownloadCompleted); webClient.DownloadProgressChanged += new DownloadProgressChangedEventHandler(FTPDownloadProgressChanged); webClient.DownloadDataAsync(new Uri("URL"));Then do the math in the callback.private void FTPDownloadProgressChanged(object sender, DownloadProgressChangedEventArgs e){ progressBar.Value = (int)(((float)e.BytesReceived / (float)bytes_total) * 100.0);} 这篇关于从FTP下载具有进度的文件 - TotalBytesToReceive总是-1？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！ 上岸，阿里云！