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在ASP.NET中用三個DropDownList控件應用

2013-11-13 09:48:56  來源: .NET編程 

  aspx頁面上有三個DropDownList控件
  
  DropDownList 表示年DropDownList表示月DropDownList表示天
  注意用將這三個DropDownList控件的AutoPostBack屬性設為True
  
  用戶可以方便地選擇年月日並且每月的日期會隨著用戶選擇不同的年月而發生相應的變化
  
  其後台cs文件代碼如下
  
   private void Page_Load(object sender SystemEventArgs e)
   {
    DateTime tnow=DateTimeNow;//現在時間
    ArrayList AlYear=new ArrayList();
    int i;
    for(i=;i<=2010;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();//綁定年
    //選擇當前年
    DropDownList1.SelectedValue=tnow.Year.ToString();
     DropDownList2.DataSource=AlMonth;
     DropDownList2.DataBind();//綁定月
    //選擇當前月
    DropDownList2.SelectedValue=tnow.Month.ToString();
    int year,month;
    year=Int32.Parse(DropDownList1.SelectedValue);
    month=Int32.Parse(DropDownList2.SelectedValue);
    BindDays(year,month);//綁定天
    //選擇當前日期
    DropDownList3.SelectedValue=tnow.Day.ToString(); 
    }
   }
  
   //判斷閏年
   private bool CheckLeap(int year)
   {
    if((year%4==0)&&(year%100!=0)||(year%400==0))
        return true;
    else return false; 
   }
   //綁定每月的天數
   private void BindDays( int year,int month)
   {  int i;
    ArrayList AlDay=new ArrayList();
     
    switch(month)
    {
     case 1:
     case 3:
     case 5:
     case 7:
     case 8:
     case 10:
     case 12:
       for(i=1;i<=31;i++)
     AlDay.Add(i);
     break;
     case 2:
     if (CheckLeap(year))
     {for(i=1;i<=29;i++)
      AlDay.Add(i);}
     else
     {for(i=1;i<=28;i++)
      AlDay.Add(i);}
     break;
     case 4:
     case 6:
     case 9:
     case 11:
     for(i=1;i<=30;i++)
     AlDay.Add(i);
     break;
        }
    DropDownList3.DataSource=AlDay;
    DropDownList3.DataBind();
   }
  
  //選擇年
   private void DropDownList1_SelectedIndexChanged(object sender, System.EventArgs e)
   {
    int year,month;
    year=Int32.Parse(DropDownList1.SelectedValue);
    month=Int32.Parse(DropDownList2.SelectedValue);
    BindDays(year,month);
   }
  //選擇月
  
   private void DropDownList2_SelectedIndexChanged(object sender, System.EventArgs e)
   {
    int year,month;
    year=Int32.Parse(DropDownList1.SelectedValue);
    month=Int32.Parse(DropDownList2.SelectedValue);
    BindDays(year,month);
   }
  

From:http://tw.wingwit.com/Article/program/net/201311/11653.html
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