private void buttonRange_Click(object sender, EventArgs e) { RangeDialog dialog = new RangeDialog(this.m_from, this.m_to); if (dialog.ShowDialog() == DialogResult.OK) { bool selected = dialog.Selected; this.checkedListBoxChannels.BeginUpdate(); for (int i = dialog.From; i <= dialog.To; i++) { this.checkedListBoxChannels.SetItemChecked(i - this.m_from, selected); } this.checkedListBoxChannels.EndUpdate(); } }