11.WinForm練習--日期選擇器

namespace _12日期選擇器
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}

    private void Form1_Load(object sender, EventArgs e)
    {
        //獲取當前時間
        int year = DateTime.Now.Year;
        //當程序運行時就將年份加載進去cboYears
        for (int i = year; i >=1949; i--)
        {
            cboYears.Items.Add(i+"年");
        }
    }

    private void cboYears_SelectedIndexChanged(object sender, EventArgs e)
    {
        //添加月份之前清空之前記錄
        cboMonths.Items.Clear();
        //當選擇年份時，加載月份
        for (int i = 1; i <= 12; i++)
        {
            cboMonths.Items.Add(i+"月");
        }
    }

    private void cboMonths_SelectedIndexChanged(object sender, EventArgs e)
    {
        //定義一個day來存儲天數
        int day = 0;
        //加載day之前清空之前記錄
        cboDays.Items.Clear();
        //獲得月份
        string strmonth = cboMonths.SelectedItem.ToString().Split(new char[] { '月' }, StringSplitOptions.RemoveEmptyEntries)[0];
        //獲得年份
        string strYear = cboYears.SelectedItem.ToString().Split(new char[] { '年' }, StringSplitOptions.RemoveEmptyEntries)[0];
        //將年月字符串類型轉換成int類型
        int year = Convert.ToInt32(strYear);
        int month = Convert.ToInt32(strmonth);
        //對month進行多條件判斷
        switch (month)
        {
            case 1:
            case 3:
            case 5:
            case 7:
            case 8:
            case 10:
            case 12:day = 31;
                break;
            case 2:if(year%400==0 || year%4==0 && year % 100 != 0)
                {
                    day = 29;
                }
                else
                {
                    day = 28;
                }
                break;
            default:day = 30;
                break;
        }
        for (int i = 1; i <= day; i++)
        {
            cboDays.Items.Add(i+"日");
        }
    }
}

}