LinqDataSource_Selecting事件未触发

Question

我有这个事件来选择我表中的最后5行并用转发器写它们但它不会触发：

protected void LinqDataSource1_Selecting(object sender, LinqDataSourceSelectEventArgs e)
{
    DataClassesDataContext db = new DataClassesDataContext();
    e.Result = db.tbl_OpenSourceNews.OrderByDescending(p => p.OpenSourceID).Take(5);
}