File closure

Question

I need to leave the file free, without getting in use, because it is blocking. Follow the code:

StringWriter sw = new StringWriter();
XmlTextWriter tw = new XmlTextWriter(sw);

XmlSerializerNamespaces xsn = new XmlSerializerNamespaces();
xsn.Add("", "http://www.portalfiscal.inf.br/nfe");

XmlSerializer ser = new XmlSerializer(typeof(TNFe));
FileStream arquivo = new FileStream("C:\\" + chave_nfe + "-NFe.xml", FileMode.CreateNew);

ser.Serialize(arquivo, nfe, xsn);

If I do:

sw.Close();

The file is still in use, and does not work as expected. What if I do:

arquivo.Dispose();

It works, only it does not monitor the folder, do not understand why this occurs, the monitoring code is soon after:

 form = new FormProgressBar();
 form.Show();

 int X = 6000;
 form.MaximumBar(X);

 // Faço o laço para atualizar a barra
 for (int i = 0; i < X; i++)
 {
       // Método que atualiza a barra e o texto da barra
       form.AtualizaBarra("Aguarde...");
       // Insiro algum código que desejo e vou mostrando o status da atualização
 }

 // clsdb.ExecutaSQL("insert into nfe (n_nota, chave) values ('" + txtnumero.Text + "','" + digito(chave) + "')");
 messagebox = 0;
 messageboxxml = 0;

 #region MONITORAR PASTA

 //Dizemos agora se é para monitorar os subdiretórios ou não
 fsw.IncludeSubdirectories = false;

 //Através de um Enum dizemos quais eventos devem ser monitorados, modificação da data do arquivo, tamanho, etc...
 fsw.NotifyFilter = NotifyFilters.FileName | NotifyFilters.LastWrite;

 //Dizemos quais tipos de arquivos devem ser monitorados, *.*, *.xml, *.txt, etc...
 //fsw.Filter = "*.xml";
 //fsw.Filter = "*.ERR";

 //Definimos agora os eventos a serem gerados
 fsw.Created += new FileSystemEventHandler(fsw_Created);
 fsw.Changed += new FileSystemEventHandler(fsw_Changed);
 fsw.Error += new ErrorEventHandler(fsw_Error);

 // A propriedade abaixo define que a monitoração deve iniciar, se false, a pasta não será monitorada
 fsw.EnableRaisingEvents = true;

That’s the code that gets both in the event Created or Changed, he does not perform.

 FileInfo fileinfo = new FileInfo(e.FullPath);

 while (arquivoTravado(fileinfo))
 {
      Thread.Sleep(1000);
 }

 System.Xml.XmlDocument xmldoc = new System.Xml.XmlDocument();

 xmldoc.Load(e.FullPath);

 if (e.FullPath.Length == 97)
 {
     System.Xml.XmlNode DadosLote = xmldoc.SelectSingleNode("DadosLoteNfe");
     System.Xml.XmlNode NumeroLote = DadosLote.SelectSingleNode("NumeroLoteGerado");

     string nlote = NumeroLote.InnerText;
     clsdb.ExecutaSQL("update nfe set num_lote = '" + nlote + "' where n_nota = '" + txtnumero.Text + "'");
  }

How can I do, so that the file is free to be treated, and the monitoring continues to work?

Answer 1

You must open the resources deform that it close itself, something like that:

using (var sw = new StringWriter())
using (var tw = new XmlTextWriter(sw))
using (var arquivo = new FileStream("C:\\" + chave_nfe + "-NFe.xml", FileMode.CreateNew) {
    // ... faz o que deve aqui
}

In C# 8 you can already do:

using var sw = new StringWriter());
using var tw = new XmlTextWriter(sw));
using var arquivo = new FileStream("C:\\" + chave_nfe + "-NFe.xml", FileMode.CreateNew);
// ... faz o que deve aqui

I put in the Github for future reference.

There are errors in the use of the form to access the database (if you take the comment), but these are other problems, it would be too broad to answer this, ask new questions.

The problem of not monitoring may be related to the fact of not having the file closed, if it is not is another problem too, and we would need more information in new question to help properly, would have to see how this pa creating monitoring, what is occurring, as tested, etc.