Question

I have the code that transfers SQL into CSV :

public void CreateCSVFile(DataTable dt, string strFilePath, bool Is_Ordre, int TypeDonne)
{

    //FileStream fs = new FileStream(strFilePath, FileMode.Create);
    // FileStream fs = File.Create(strFilePath);

    // Create the CSV file to which grid data will be exported.
    //StreamWriter sw = new StreamWriter(fs);
    //StreamWriter sw = new StreamWriter(strFilePath, false);
    using (var sw = new StreamWriter(strFilePath, false))
    {
        // First we will write the headers.
        //DataTable dt = m_dsProducts.Tables[0];
        int iColCount = dt.Columns.Count;
        for (int i = 0; i < iColCount; i++)
        {
            sw.Write(dt.Columns[i]);
            if (i < iColCount - 1)
            {
                sw.Write(",");
            }
        }
        if (Is_Ordre) sw.Write(", TYP_DONNE");

        sw.Write(sw.NewLine);

        // Now write all the rows.
        foreach (DataRow dr in dt.Rows)
        {
            for (int i = 0; i < iColCount; i++)
            {
                if (!Convert.IsDBNull(dr[i]))
                {
                    sw.Write("\'" + dr[i].ToString().Replace("'", " ").Replace(",", ".") + "\'");
                }
                else
                {
                    sw.Write("\' \'");
                }
                if (i < iColCount - 1)
                {
                    sw.Write(",");
                }
            }
            if (Is_Ordre) sw.Write(", \'" + TypeDonne + "\'");
            sw.Write(sw.NewLine);
        }                
        sw.Flush();
        sw.Close();
        sw.Dispose();
    }
        //fs.Close();

}

After that I send the CSV file via email:

Attachment data_OD = new Attachment(LeSource, MediaTypeNames.Application.Octet);
Attachment data_LV = new Attachment(LeSource_LV, MediaTypeNames.Application.Octet);
oEmail.SendingEmail(ClientID,  data_OD, data_LV);

public void SendingEmail(string CodeClient, Attachment dataOD, Attachment dataLV)
{
    try
    {
        Pers_Conf oConf = LeConf.Get_Config(CodeClient);

        MailMessage omail = new MailMessage();
        var oSmtp = new SmtpClient("smtp.gmail.com", 587)
        {
            Credentials = new NetworkCredential("[e-mail]", "xxxxxx"),
            EnableSsl = true
        };

        omail.From = new MailAddress("[e-mail]");               
        omail.To.Add(oConf.EmailAddr);
        omail.Subject = "xxxxxx_" + CodeClient;
        omail.Body = CodeClient;

        omail.Attachments.Add(dataOD);
        omail.Attachments.Add(dataLV);

        oSmtp.Send(omail);
    }
    catch (Exception excThrown)
    {
        throw excThrown;
    }

it seems that StreamWriter does not properly close the file, I already try with this :

    Try
    {
    StreamWriter sw = new StreamWriter(strFilePath, false);
    }
    Catch
    {
    }
    Finaly
    {
     sw.Flush();
     sw.Close();
     sw.Dispose();
}

but in the finally block it does not recognize sw.

Any idea ?

PS: this line of code throws an exception that tell that the file is being use by other process

 using (var sw = new StreamWriter(strFilePath, false))

is not closing because of StreamWriter not properly close or it is because send email is using this file ?

Answer 1

Supposing you enter in this code more than one time.
In either case you need to call the MailMsg.Dispose() of the MailMessage class.
Otherwise, it will hold the attachment resulting in a file locked the next time you try to write in it.

Try to use the using statement also on the MailMessage

        try 
        { 
            Pers_Conf oConf = LeConf.Get_Config(CodeClient); 

            using(MailMessage omail = new MailMessage())
            {
                .....
                oSmtp.Send(omail); 
            }
        } 
        catch (Exception excThrown) 
        { 
            throw excThrown; 
        }