int year, month; protected void Page_Load(object sender, EventArgs e) { DateTime tnow = DateTime.Now; ArrayList AlYear = new ArrayList(); int i; for (i = 2002; i <= 2012; i++) AlYear.Add(i); ArrayList AlMonth = new ArrayList(); for (i = 1; i <= 12; i++) AlMonth.Add(i); if (!this.IsPostBack) { DropDownList1.DataSource = AlYear; DropDownList1.DataBind(); DropDownList1.SelectedValue = tnow.Year.ToString(); DropDownList2.DataSource = AlMonth; DropDownList2.DataBind(); DropDownList2.SelectedValue = tnow.Month.ToString(); year = Int32.Parse(DropDownList1.SelectedValue); month = Int32.Parse(DropDownList2.SelectedValue); BindDays(year, month); DropDownList3.SelectedValue = tnow.Day.ToString(); } Label1.Text = "You select date:" + DropDownList1.SelectedValue + "year" + DropDownList2.SelectedValue + "month" + DropDownList3.SelectedValue; } //judge leap year private bool CheckLeap(int year) { if ((year % 4 == 0) && (year % 100 != 0) || (year % 400 == 0)