private void btnCancle_Click(object sender, EventArgs e)
{
//直接根据选中的项的数量来还原
string result = null;
int n = clbHistory.CheckedItems.Count;
for (int i = 0; i < n; i++)
{
result = StaticSQLiteHelper.Recovery();
}
//string result=StaticSQLiteHelper.Recovery();
if (result == null)
{
MessageBox.Show("已经没有可以撤销的操作！");
}
else
{
//MessageBox.Show(result);
schedule = new Schedule(StaticSQLiteHelper.GetSchedule());
nightSchedule = new Schedule(StaticSQLiteHelper.GetNightSchedule());
loadClassSchedule(currentClassID);
loadHistory();
}
}