本文主要是介绍dropdownlist 显示日期，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！
dropdownlist1代表年 autopostback=true
dropdownlist2代表月 autopostback=true
dropdownlist3代表日
protected void Page_Load( object sender, EventArgs e)
... {
string s = Request.QueryString["id"]; Response.Write(Server.UrlDecode(s)); DateTime tnow = DateTime.Now; ArrayList years = new ArrayList(); ArrayList months = new ArrayList(); int i; for (i = 1991; i >= 1958; i--)
...{ years.Add(i);
} for (i = 1; i <= 12; i++) ...{ months.Add(i); } if (!IsPostBack) ...{ DropDownList1.DataSource = years; DropDownList1.SelectedValue =years[8].ToString(); DropDownList1.DataBind(); DropDownList2.DataSource = months; DropDownList2.SelectedValue = tnow.Month.ToString(); DropDownList2.DataBind(); int year, month; Int32.TryParse(tnow.Year.ToString(), out year); Int32.TryParse(tnow.Month.ToString(), out month); binddropdownlist3(year, month); DropDownList3.SelectedValue = tnow.Day.ToString(); }
} protected bool checkLeap( int year) ... { if ((year % 4 != 0) && (year % 100 != 0) || (year % 400 == 0)) ...{ return true; } else ...{ return false; } } protected void binddropdownlist3( int year, int month) ... { int i; ArrayList days = new ArrayList(); switch (month) ...{ case 1: case 3: case 5: case 7: case 8: case 10: case 12: for (i = 1; i <= 31; i++) ...{ days.Add(i); } break; case 2: if (checkLeap(year)) ...{ for (i = 1; i <= 29; i++) ...{ days.Add(i); } } else ...{ for (i = 1; i <= 28; i++) ...{ days.Add(i); } } break; case 4: case 6: case 9: case 11: for (i = 1; i <= 30; i++) ...{ days.Add(i); } break; } DropDownList3.DataSource = days; DropDownList3.DataBind(); } protected void DropDownList1_SelectedIndexChanged( object sender, EventArgs e) ... { int year, month; Int32.TryParse(DropDownList1.SelectedValue.ToString(), out year); Int32.TryParse(DropDownList2.SelectedValue.ToString(),out month); binddropdownlist3(year, month); } protected void DropDownList2_SelectedIndexChanged( object sender, EventArgs e) ... { int year, month; Int32.TryParse(DropDownList1.SelectedValue.ToString(),out year); Int32.TryParse(DropDownList2.SelectedValue.ToString(),out month); binddropdownlist3(year, month); } 但是这种做法会刷新页面，不是很好！
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