我编译时出错 [英] Error when i compile

问题描述

我在运行它时遇到错误，它说输入字符串的格式不正确.有人可以帮忙吗，我已经尝试了一切

I get an error when I run it, it says Input string was not in a correct format. can someone please assist, I have tried everything

public partial class Test : System.Web.UI.Page
    {
        private void Page_Load(object sender, EventArgs e)
        {
            if (!IsPostBack)
            {
                ddlMonth.DataSource = Enumerable.Range(1, 12).Select(a => new
                {
                    MonthName = DateTimeFormatInfo.CurrentInfo.GetMonthName(a),
                    MonthNumber = a
                }
                );
                ddlMonth.DataBind();
                ddlYear.DataSource = Enumerable.Range(DateTime.Now.Year - 99, 100).Reverse();
                ddlYear.DataBind();
                ddlday.DataSource = Enumerable.Range(1, DateTime.DaysInMonth(DateTime.Now.Year, Convert.ToInt32(ddlMonth.SelectedValue)));
                ddlday.DataBind();
            }
        }

        protected void ddlMonth_SelectedIndexChanged(object sender, EventArgs e)
        { ddlday.DataSource = Enumerable.Range(1, DateTime.DaysInMonth(DateTime.Now.Year, Convert.ToInt32(ddlMonth.SelectedValue))); ddlday.DataBind(); }

        public bool IsPostBack { get; set; }
    }
}

推荐答案

我认为是Convert.ToInt32(ddlMonth.SelectedValue); ...
``ddlMonth.SelectedValue''不是有效的整数字符串.

//先检查//
MessageBox.show(ddlMonth.SelectedValue.toString());
它将显示整数字符串.
确保这是一个有效的整数字符串.

I think in Convert.ToInt32(ddlMonth.SelectedValue); ...
''ddlMonth.SelectedValue'' is not a valid integer string.

//Check it first//
MessageBox.show(ddlMonth.SelectedValue.toString());
it will show integer string.
Make sure this is a valid integer string.

尝试一下此

Try this

private void Page_Load(object sender, EventArgs e)
        {
            if (!IsPostBack)
            {
                ddlMonth.DataSource = Enumerable.Range(1, 12).Select(a => new
                {
                    MonthName = DateTimeFormatInfo.CurrentInfo.GetMonthName(a),
                    MonthNumber = a
            //DataTextField = DateTimeFormatInfo.CurrentInfo.GetMonthName(a),
            //DataValueField = a
              }
                );

        //If this code is not working then try the above code in the loop.
        ddlMonth.DataTextField="MonthName";
        ddlMonth.DataValueField="MonthNumber";

                ddlMonth.DataBind();
                ddlYear.DataSource = Enumerable.Range(DateTime.Now.Year - 99, 100).Reverse();
                ddlYear.DataBind();
                ddlday.DataSource = Enumerable.Range(1, DateTime.DaysInMonth(DateTime.Now.Year, Convert.ToInt32(ddlMonth.SelectedValue)));
                ddlday.DataBind();
            }
        }

替换

ddlday.DataSource = Enumerable.Range(1，DateTime.DaysInMonth(DateTime.Now.Year，Convert.ToInt32(ddlMonth.SelectedValue))));

与

ddlday.DataSource = Enumerable.Range(1，DateTime.DaysInMonth(DateTime.Now.Year，Convert.ToInt32(ddlMonth.SelectedIndex + 1))));

我认为这可以解决您的问题.

Replace

ddlday.DataSource = Enumerable.Range(1, DateTime.DaysInMonth(DateTime.Now.Year, Convert.ToInt32(ddlMonth.SelectedValue)));

with

ddlday.DataSource = Enumerable.Range(1, DateTime.DaysInMonth(DateTime.Now.Year, Convert.ToInt32(ddlMonth.SelectedIndex + 1)));

I think this will solve your issue.

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