将 DateTime.Now 与存储在 SQL 中的值进行比较

Question

I am converting ADODB namespace code to SqlClient . I am trying to replace code that utilized recordset.Value . I am having problems converting this line of code. How can I subtract DateTime.Now from the value in the time_of_lock (Datetime data type) column in SQL ?

else if (DateTime.Now - rs.Fields["time_of_lock"].Value < TimeSpan.FromMinutes(15))

Answer 1

I am assuming you can get two DateTime values from your code. If so, try pop both into the following function:

private bool TimesApartNoMoreThan(DateTime first, DateTime second, int threshold) 
{
    return (second - first).TotalMinutes > threshold;
}

when you subtract two DateTimes, you get a TimeSpan . Having obtained that, you can represent it as whatever unit of duration you need ( in this case, minutes ):

Answer 2

From your statement, I am assuming rs.Fields["time_of_lock"] is of DateTime datatype. If that is the case, please try this:

DateTime.Now .Subtract(rs.Fields["time_of_lock"].Value).TotalMinutes < 15