Question

The above error message appears when I am trying to get Column Value from Datatable.

This is what I find in the stacktrace:

System.Linq.Enumerable.WhereSelectEnumerableIterator2.MoveNext()
at System.Linq.Enumerable.FirstOrDefault[TSource](IEnumerable1
source)

 and this in the TargetSite when debugging:

{ Boolean b__0(System.Data.DataRow)}

Here is my code:
DataTable hr = new DataTable();

            hr.Columns.Add("BookingDate");
            hr.Columns.Add("BookingId");
            hr.Columns.Add("BookingSource");
            hr.Columns.Add("CheckInDate");
            hr.Columns.Add("CheckOutDate");


            for (int i = 0; i < gmisc.GetModifiedBookings(gmoreq).Bookings.Length; i++)
            {
                hr.Rows.Add();
                hr.Rows[i]["BookingDate"] = Convert.ToDateTime(gmisc.GetModifiedBookings(gmoreq).Bookings[i].BookingDate.ToString());
                hr.Rows[i]["BookingId"] = Convert.ToInt64(gmisc.GetModifiedBookings(gmoreq).Bookings[i].BookingId.ToString());
                hr.Rows[i]["BookingSource"] = gmisc.GetModifiedBookings(gmoreq).Bookings[i].BookingSource.ToString();
                hr.Rows[i]["CheckInDate"] = Convert.ToDateTime(gmisc.GetModifiedBookings(gmoreq).Bookings[i].CheckInDate.ToString());
                hr.Rows[i]["CheckOutDate"] = Convert.ToDateTime(gmisc.GetModifiedBookings(gmoreq).Bookings[i].CheckOutDate.ToString());



            }
            Int64 BookingId = (from DataRow dr in hr.Rows
                          where (Int64)dr["BookingId"] == BookId
                          select (Int64)dr["BookingId"]).FirstOrDefault();
                TextBox1.Text = Convert.ToString(BookingId);

Where did I go wrong, if somebody can please tell me.

Answer 1

Check your code, the very first two lines:

hr.Rows[i]["BookingDate"] = Convert.ToDateTime(gmisc.GetModifiedBookings(gmoreq).Bookings[i].BookingDate.ToString());
hr.Rows[i]["BookingId"] = Convert.ToInt64(gmisc.GetModifiedBookings(gmoreq).Bookings[i].BookingId.ToString());

if gmisc.GetModifiedBookings(gmoreq).Bookings[i].BookingDate is null then ???
you are trying to convert it into string and then to datetime

if null then .ToString will give error “Specified cost…….”

and same will happen at the time of converting to datetime.