Cannot access a disposed object. Object name: System.Net.Sockets.NetworkStream

Question

I am using CsvHelper. Here I am trying to download a csv file from ftp and write to a class. It's throwing an error - Cannot access a disposed object. Object name: System.Net.Sockets.NetworkStream. from line - IEnumerable records = csv.GetRecords().ToList();

Any idea?

            request.Credentials = new NetworkCredential(ftpUser, ftpPwd);
            request.Method = WebRequestMethods.Ftp.DownloadFile;
            request.UseBinary = true;

            // Csv file
            using (FtpWebResponse response = (FtpWebResponse)request.GetResponse())
            {
                using (Stream responseStream = response.GetResponseStream())
                {
                    if (responseStream != null)
                    {
                        using (TextReader tr = new StreamReader(responseStream))
                        {
                            using (CsvReader csv = new CsvReader(tr))
                            {
                                if (csvUpload.IncludeInvoice) csv.Configuration.RegisterClassMap<PacketUploadInvoiceMasterMap>();
                                else csv.Configuration.RegisterClassMap<PacketUploadBasicMasterMap>();

                                IEnumerable<PacketUploadMaster> records = csv.GetRecords<PacketUploadMaster>().ToList();

                                pumResults = records.ToList();
                            }
                        }
                    }
                }

                response.Close();
            }

Isbell

you shouldn't call close and use it as a disposable. – Excellence

that does not resolve the issue though – Isbell

could you elaborate, what library (CsvReader) do you use? – Leduc

CsvHelper joshclose.github.io/CsvHelper – Isbell

There is a known issue when Read returns 0 bytes it will close the stream developercommunity.visualstudio.com/t/… – Paddlefish

Answer 1

In order to fix this issue, I had to do File reading and writing in csv separately like below

using (FtpWebResponse response = (FtpWebResponse)request.GetResponse())
using (Stream responseStream = response.GetResponseStream())
{
    if (responseStream != null)
    {
        using (MemoryStream ms = new MemoryStream())
        {
            responseStream.CopyTo(ms);
            streamInByte = ms.ToArray();
        }
    }
}

using (TextReader tr = new StreamReader(new MemoryStream(streamInByte), Encoding.Default))
{
    using (CsvReader csv = new CsvReader(tr))
    {
        // The value used to escape fields that contain a delimiter, quote, or line ending.
        // csv.Configuration.Quote = '"';
        if (csvUpload.IncludeInvoice) csv.Configuration.RegisterClassMap<PacketUploadInvoiceMasterMap>();
        else csv.Configuration.RegisterClassMap<PacketUploadBasicMasterMap>();

        // Remove white space from header
        csv.Configuration.TrimHeaders = true;

        IEnumerable<PacketUploadMaster> records = csv.GetRecords<PacketUploadMaster>().ToList();

        pumResults = records.ToList();
    }
}

Isbell

Answer 2

When the using of responseStream ends, it will close and dispose both the responseStream and its underlying stream which happens to be your FtpWebResponse response. Which is why calling response.Close() will throw Cannot access a disposed object.

Swindle