Adding Seconds to DateTime with a Valid Double Results in ArgumentOutOfRangeException

Question

The following code crashes and burns and I don\'t understand why:

DateTime dt = new DateTime(1970,1,1,0,0,0,0, DateTimeKind.Utc);
double d = double.Parse(\"1         


        

Answer 1

I had a similar issue where I was required to add a configurable timespan to a datetime. If the configuration is not correct I have to assume the 'worst scenario' : MaxValue.

I solved it by implementing an extension to DateTime (still in test phase) :

    /// <summary>
    /// Removes a timespan from a date, returning MinValue or MaxValue instead of throwing exception when if the resulting date
    /// is behind the Min/Max values
    /// </summary>
    /// <returns></returns>
    public static DateTime SafeAdd(this DateTime source, TimeSpan value)
    {
        // Add or remove ?
        if (value.Ticks > 0)
        {
            // add
            var maxTicksToAdd = DateTime.MaxValue - source;
            if (value.Ticks > maxTicksToAdd.Ticks)
                return DateTime.MaxValue;
        }
        else
        {
            var maxTicksToRemove = source - DateTime.MinValue;

            // get the value to remove in unsigned representation.
            // negating MinValues is impossible because it would result in a value bigger than MaxValue : (-32768 .. 0 .. 32767)
            var absValue = value == TimeSpan.MinValue ? TimeSpan.MaxValue : -value;

            if (absValue.Ticks > maxTicksToRemove.Ticks)
                return DateTime.MinValue;
        }
        return source + value;
    }