由于某些防火墙问题，我们需要使用“主动”模式（即不是通过启动PASV命令）进行 FTP。
目前，我们正在使用以下代码：
// Get the object used to communicate with the server.
FtpWebRequest request = (FtpWebRequest)WebRequest.Create("ftp://www.contoso.com/test.htm");
request.Method = WebRequestMethods.Ftp.UploadFile;
// This example assumes the FTP site uses anonymous logon.
request.Credentials = new NetworkCredential ("anonymous","janeDoe@contoso.com");
// Copy the contents of the file to the request stream.
StreamReader sourceStream = new StreamReader("testfile.txt");
byte [] fileContents = Encoding.UTF8.GetBytes(sourceStream.ReadToEnd());
sourceStream.Close();
request.ContentLength = fileContents.Length;
Stream requestStream = request.GetRequestStream();
requestStream.Write(fileContents, 0, fileContents.Length);
requestStream.Close();
FtpWebResponse response = (FtpWebResponse)request.GetResponse();
response.Close();
但这似乎默认使用被动模式；我们可以影响它以强制它使用主动模式上传（以与命令行 ftp 客户端相同的方式）？