private void btnAssinar_Click(object sender, EventArgs e) { if (openFileDialog1.ShowDialog() == DialogResult.OK) { btnAssinar.Enabled = false; asscshnfse.asscshnfse nfse = new asscshnfse.asscshnfse(); string tmp = nfse.AssinarArquivoXML(openFileDialog1.FileName, "TipoRPS"); MessageBox.Show(tmp); btnAssinar.Enabled = true; } }