private void openToolStripMenuItem_Click(object sender, EventArgs e) { using (OpenFileDialog ofd = new OpenFileDialog()) { //ofd.Filter = "CSV files(*.csv)| *.csv | XML files(*.xml) | *.xml"; if (ofd.ShowDialog() == DialogResult.OK) { string ext = Path.GetExtension(ofd.FileName); database.FileName = ofd.FileName; //MessageBox.Show(ext); if (ext == ".csv" || ext == ".CSV") { database.Convert(); this.csv = true; } else { database.Load(); this.csv = false; } nudNumber.Minimum = 1; nudNumber.Maximum = database.Count; nudNumber.Value = 1; } } }