EpgTimer.SetApp2DelWindow.button_chk_add_Click C# (CSharp) Method

        private void button_chk_add_Click(object sender, RoutedEventArgs e)
        {
            if (String.IsNullOrEmpty(textBox_chk_folder.Text) == false)
            {
                foreach (String info in listBox_chk_folder.Items)
                {
                    if (String.Compare(textBox_chk_folder.Text, info, true) == 0)
                    {
                        MessageBox.Show("すでに追加されています");
                        return;
                    }
                }
                listBox_chk_folder.Items.Add(textBox_chk_folder.Text);
            }
        }