Question

我正在尝试设置月，日输入为此，我有2个字段第1个 A DropDownList，允许用户选择month。

<asp:DropDownList ID="month" runat="server" onchange="refSelect();"></asp:DropDownList>

第二名：select，允许用户选择day

<select ID="day" runat="server"></select>

每当用户更改month时，JavaScript函数都会更新您可以在day字段中选择的日期。
month和day字段的选项都加载在page_load后面的代码中我遇到的问题是，无论何时加载页面并将month字段设置为（例如2月），用户都会更改为1月的另一个月，并选择一天> 28代码后面将所选日期保存为1.

int test = day.Value; //test will equal 1

如果用户选择任何一天<= 28，则后面的代码会保存他们选择的任何内容。 JavaScript：

var Months = {
    "January": function () { return 31; },
    "February": function () { return 28; },
    "March": function () { return 31; },
    "April": function () { return 30; },
    "May": function () { return 31; },
    "June": function () { return 30; },
    "July": function () { return 31; },
    "August": function () { return 31; },
    "September": function () { return 30; },
    "October": function () { return 31; },
    "November": function () { return 30; },
    "December": function () { return 31; }
    }
    refSelect: function () {
        var month = document.getElementById("month");
        var day = document.getElementById("day");
        var monthSelected = month.options[month.selectedIndex].text;            
        daysTotal = Months[monthSelected]();
        if (day.options.length > daysTotal) {
            day.options.length = daysTotal;
        }
        else if(day.options.length < daysTotal) {
            while (day.options.length < daysTotal) {
                var option = document.createElement('option');
                option.text = option.value = day.options.length + 1;
                day.add(option);
                day.options[day.options.length] = option;
            }
        }

有谁知道如何防止这种情况发生？

代码背后：

//redirects to another page after executing
protected void btnSave_Click(object sender, EventArgs e)
{
    int month = (DropDownList)Page.FindControl("month").SelectedValue;
    int day= (HtmlSelect)Page.FindControl("day").Value;

    string monthDay = String.Format("{0}/{1}", month, day);
    User.SaveSelectedDate(monthDay);
}

protected void Page_Load(object sender, EventArgs e)
{
    if (!IsPostBack)
    {
       LoadDropDowns();
    }
}

private void LoadDropDowns()
{
    string saved = User.GetSavedDate();
    DropDownList month = (DropDownList)Page.FindControl("month");
    HtmlSelect day= (HtmlSelect)Page.FindControl("day");

    string[] split = saved.Split('/');

    DateTime start = new DateTime(1, 1, 1);
    for (int j = 0; j < 12; j++)
    {
        DateTime current = start.AddMonths(j);
        month.Items.Add(new ListItem(String.Format("{0:MMMM}", current), current.Month.ToString()));                    
    } 

    month.SelectedValue = split[0];

    for (int d = 1; d <= DateTime.DaysInMonth(1, Int32.Parse(month.SelectedValue)); d++)
    {
        day.Items.Add(new ListItem(d.ToString(), d.ToString()));
    }

    day.Value = Int32.Parse(split[1]);
}

HTML选择不保存选定的值

0 个答案: