private void combineButton_Click(object sender, EventArgs e) { if (saveFileDialog.ShowDialog() == DialogResult.OK) { using (var combiner = new Combiner(saveFileDialog.FileName)) { progressBar.Visible = true; this.Enabled = false; for (int i = 0; i < inputListBox.Items.Count; i++) { combiner.AddFile((string)inputListBox.Items[i]); progressBar.Value = (int)(((i + 1) / (double)inputListBox.Items.Count) * 100); } this.Enabled = true; progressBar.Visible = false; } System.Diagnostics.Process.Start(saveFileDialog.FileName); } }