通过FTP上传大文件时出错

Question

我正在尝试通过以下代码上传4 GB的zip文件。

相同的代码适用于较小的文件，但它不适用于大文件。我认为在关闭FileStream时会生成异常。

我收到此错误：

  

消息：基础连接已关闭：接收时发生意外错误。 Stacktrace：位于系统System.IO.Stream.Close（）的System.Net.CommandStream.Dispose（布局处理）的System.Net.FtpWebRequest.RequestCallback（Object obj）处的System.Net.FtpWebRequest.SyncRequestCallback（Object obj）处System.Net.FtpWebRequest.FinishRequestStage上System.Net.ConnectionPool.PutConnection（PooledStream pooledStream，Object owningObject，Int32 creationTimeout，Boolean canReuse）的System.Net.ConnectionPool.Destroy（PooledStream pooledStream）中的.IO.Stream.Dispose（）处于System.Net.FtpWeb上的System.Net.FtpWebRequest.SallRequestCallback（Object obj）处的System.Net.FtpWebRequest.RequestCallback（Object obj）处的System.Net.Com.St.DemandCream（（例外））处于System.Net.Com.St.DemandCream（在System.IO.Stream.Close上的System.Net.FtpDataStream.Dispose（布尔处理）处的System.Net.FtpDataStream.System.Net.ICloseEx.CloseEx（CloseExState closeState）处的System.Net.FtpWebRequest.DataStreamClosed（CloseExState closeState）（ ）在BackupUtility的System.IO.Stream.Dispose（）处。 Program.UploadFileToFTP（String source）

我的FTP代码是：

private static bool UploadFileToFTP(string source)
{
    try
    {
        String sourcefilepath = source; // e.g. "d:/test.docx"
        String ftpurl = "myftpurl";

        String ftpusername = "ftpusername"; // e.g. username
        String ftppassword = "ftppassword"; // e.g. password

        string ftpfullpath = "mylocalftpFilePath";

        Console.WriteLine("Before Request. ftpfullpath:" + ftpfullpath);
        //  Console.ReadLine();

        FtpWebRequest ftp = (FtpWebRequest)FtpWebRequest.Create(ftpfullpath);
        ftp.Credentials = new NetworkCredential(ftpusername, ftppassword);

        ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12;

        ftp.KeepAlive = true;
        ftp.UseBinary = true;
        ftp.Timeout = 6000000;

        ftp.Method = WebRequestMethods.Ftp.UploadFile;

        FileStream fs = File.OpenRead(source);

        byte[] buffer = new byte[8192];
        using (Stream ftpstream = ftp.GetRequestStream())
        {
            //Stream ftpstream = ftp.GetRequestStream();
            int read = 0;
            while ((read = fs.Read(buffer, 0, buffer.Length)) != 0)
            {
                ftpstream.Write(buffer, 0, read);
            }
            ftpstream.Flush();
        }

        fs.Read(buffer, 0, buffer.Length);
        fs.Close();
    }
    catch (Exception ex)
    {
        return false;
    }
    return true;
}