private void 게임삭제DToolStripMenuItem_Click(object sender, EventArgs e)
 {
     ListView.SelectedListViewItemCollection selectedItems = lvParty.SelectedItems;
     if ((selectedItems.Count > 0) && (MessageBox.Show($"{selectedItems.Count}개 항목을 삭제할까요?", "Swiss Tournament", MessageBoxButtons.YesNo, MessageBoxIcon.Asterisk) == DialogResult.Yes))
     {
         foreach (int num in from x in selectedItems.OfType <ListViewItem>() select x.SubItems[0].Text.ToInt32())
         {
             MainForm.Instance.Manager.RemoveHistory(num);
         }
         Refresh();
     }
 }