C# // Stream writer Problem

Stream file = openFileDialog1.OpenFile();
            StreamWriter writer = new StreamWriter(file);


            writer.WriteLine(string.Format("{0};{1};{2};{3};{4}",m_einstellungen.Time,m_einstellungen.Passwort_one,m_einstellungen.Passwort_two,m_einstellungen.beenden_passwort, m_einstellungen.maxpasswortlänge));
            writer.Close();
            file.Close();