datetime parsing from excel sheet in asp.net - asp.net

Question

i want to get a datetime value from excel sheet and take the highest and the lowest date
i read the excel sheet and put it in datatable :
i tried this code :
protected void CheckTheFP(DataTable data)
{
if (data.Rows.Count != 0)
{
DateTime ds = new DateTime();
err.Text = DateTime.TryParseExact(data.Rows[0][2].ToString(), "MM/dd/yy hh:mm tt",
CultureInfo.InvariantCulture,
System.Globalization.DateTimeStyles.None,
out ds) + "" ;
}
}
but i always get false ... don't know why ?
and is there a way to sort this datatable or take the highest and lowest date
this the excel sheet i read from

Answer 1

This format string should work: "M/dd/yy h:mm tt". I've used single M because the month has one digit, the same applies to the hours. I've used CultureInfo.InvariantCulture to prevent that all / will be replaced with your actual date-separator (in case that it's different).
You can use LINQ:
var allDateTimes = data.AsEnumerable()
.Select(row => DateTime.ParseExact(row.Field<string>("Time"), "M/dd/yy h:mm tt", CultureInfo.InvariantCulture));
DateTime min = allDateTimes.Min();
DateTime max = allDateTimes.Max();
If you want to be on the safe side you should use TryParseExact, for example with this code:
IEnumerable<DateTime> allDateTimes = data.AsEnumerable()
.Select(row => {
string time = row.Field<string>("Time").Trim();
DateTime dt;
if (DateTime.TryParseExact(time, "M/dd/yy h:mm tt", CultureInfo.InvariantCulture, DateTimeStyles.None, out dt))
return (DateTime?) dt;
return null; // set a breakpoint here to see which value could not be parsed
})
.Where(dt => dt.HasValue)
.Select(dt => dt.Value);
DateTime min = allDateTimes.Min();
DateTime max = allDateTimes.Max();
Edit: you: "when i try to use it on the date 11/2/14 4:42 PM you see the 11 is not in M datetime format
The month is not the problem. Use single d instead because the days can have a single digit also.
So: "M/d/yy h:mm tt"