c# - 如何将值动态设置为下拉列表？

Question

让我们考虑一下我有两个日期字段。

DateTime dt1 = "01/04/2012"
DateTime dt2 = "31/08/2012"

这里我的日期是“DD/MM/YYYY”格式。这里 dt1 是开始日期，dt2 是结束日期。从两个日期字段中，我可以知道它位于 04,05,06,07,08 月份。

所以我想在我的下拉列表中显示月份和年份的组合。

04/2012
05/2012
06/2012
07/2012
08/2012

我怎样才能做到这一点？

Answer 1

如果 Asp.net：

   DateTime dt1 = new DateTime();
    dt1 = DateTime.ParseExact("01/04/2012", "dd/MM/yyyy", CultureInfo.InvariantCulture);
    DateTime dt2 = new DateTime();
    dt2 = DateTime.ParseExact("31/08/2012", "dd/M/yyyy", CultureInfo.InvariantCulture);
    while (dt2 > dt1)
    {
        dt1 = dt1.AddMonths(1);
        this.dateDropDownList.Items.Add(dt1.ToString("MM / yyyy", CultureInfo.InvariantCulture));
    }

如果窗口形式：

    DateTime dt1 = new DateTime();
    dt1 = DateTime.ParseExact("01/04/2012", "dd/MM/yyyy", CultureInfo.InvariantCulture);
    DateTime dt2 = new DateTime();
    dt2 = DateTime.ParseExact("31/08/2012", "dd/M/yyyy", CultureInfo.InvariantCulture);
    while (dt2 > dt1)
    {
        dt1 = dt1.AddMonths(1);
        this.dateComboBox.Items.Add(dt1.ToString("MM / yyyy", CultureInfo.InvariantCulture));
    }

Answer 2

        DateTime dt1 = new DateTime(2012,04,01);
        DateTime dt2 = new DateTime(2012,08,30);

        int firstMonth = dt1.Month;
        int lastMonth =dt2.Month;
        //Then you can compare the two numbers as you like

Answer 3

Something like below will give you a list of string, that you can use to bind to the drop down.

 DateTime dt1 = DateTime.ParseExact("01/04/2012", "d/M/yyyy", CultureInfo.InvariantCulture);
 DateTime dt2 = DateTime.ParseExact("31/08/2012", "d/M/yyyy", CultureInfo.InvariantCulture);
List<string> list = new List<string>();
while (dt2 > dt1)
     {
      list.Add(dt1.Month + "/" + dt1.Year);
      dt1 = dt1.AddMonths(1);
      }

If you output it using foreach you will get:

    foreach (string str in list)
    {
        Console.WriteLine(str);
    }


4/2012
5/2012
6/2012
7/2012
8/2012

Later if its ASP.Net (because you used dropdownlist), you can do

    DropDownList1.DataSource = list;
    DropDownList1.DataBind();

Answer 4

你可以这样做：

int firstMonth = Int32.Parse(dt1.Month);
int secondMonth = Int32.Parse(dt2.Month);
int year = Int32.Parse(dt1.Year);
// You could do some checking if the year is different or something.
for(int month = firstMonth; month <= secondMonth; month++)
    // Add the date to the drop down list by using (month + year).ToString()

希望这可以帮助！