string[] txt = new string[2000];
            OpenFileDialog ofd = new OpenFileDialog();
            SaveFileDialog sfd = new SaveFileDialog();
            if (ofd.ShowDialog() == DialogResult.OK)
            {
                if (sfd.ShowDialog() == DialogResult.OK) ;
                {
                    FileStream fs1 = new FileStream(ofd.FileName, FileMode.Open, FileAccess.Read, FileShare.Read);
                    StreamReader sr = new StreamReader(fs1, Encoding.Default);
                    FileStream fs2 = new FileStream(sfd.FileName, FileMode.Create, FileAccess.Write, FileShare.Write);
                    StreamWriter sw = new StreamWriter(fs2, Encoding.Default);

                    int i = 0;
                    string zeile;
                    while ((zeile = sr.ReadLine()) != null)
                        txt[i++] = zeile;
                    while (i > 0)
                        sw.WriteLine(txt[--i]);
                }
            }