输入字符串的日期时间格式不正确

Question

I have a DatePicker from whose value I am trying to insert to an SQL Server table's Date field.

tbl_leave_student updateStdLeave = new tbl_leave_student{
                leave_from=Convert.ToDateTime( dpLeaveFromStd.SelectedDate.GetValueOrDefault())
            };
            db.tbl_leave_students.InsertOnSubmit(updateStdLeave);
            db.SubmitChanges();

This gives a Format Exception with the message

Input string was not in a correct format

I've tried inserting without the Convert.ToDateTime and also dpLeaveFromStd.SelectedDate (without the .GetValueOrDefault()) and got the same error. Any reason why?

Answer 1

你可以做如下

leave_from = dpLeaveFromStd.SelectedDate ?? DateTime.Now;

Answer 2

you should always use D ateTime.TryParseExact .

string[] formats = { "dddd, dd MMMM yyyy" };  //your format here
DateTime dt;
if (DateTime.TryParseExact(dpLeaveFromStd.SelectedDate.GetValueOrDefault(), formats, CultureInfo.InvariantCulture, DateTimeStyles.None, out dt))
{

}

Answer 3

I guess you are using a Nullable DatePicker and probably you would be getting a null value,

So you should try to modify the code as

leave_from = dpLeaveFromStd.SelectedDate.GetValueOrDefault(DateTime.Now);

So this would set it to a default to Today if the value is null