Compare nullable datetime objects

Nullable.Equals Indicates whether two specified Nullable(Of T) objects are equal.

Try:

if(birthDate.Equals(hireDate))

The best way would be: Nullable.Compare Method

Nullable.Compare(birthDate, hireDate));

To compare two Nullable<T> objects use Nullable.Compare<T> like:

bool result = Nullable.Compare(birthDate, hireDate) > 0;

---

You can also do:

Use the Value property of the Nullable DateTime. (Remember to check if both object Has some values)

if ((birthDate.HasValue && hireDate.HasValue) 
    && DateTime.Compare(birthDate.Value, hireDate.Value) > 0)
{
}

If both values are Same DateTime.Compare will return you 0

Something Like

DateTime? birthDate = new DateTime(2000, 1, 1);
DateTime? hireDate = new DateTime(2013, 1, 1);
if ((birthDate.HasValue && hireDate.HasValue) 
    && DateTime.Compare(birthDate.Value, hireDate.Value) > 0)
{
}

If you want a null value to be treated as default(DateTime) you could do something like this:

public class NullableDateTimeComparer : IComparer<DateTime?>
{
    public int Compare(DateTime? x, DateTime? y)
    {
        return x.GetValueOrDefault().CompareTo(y.GetValueOrDefault());
    }
}

and use it like this

var myComparer = new NullableDateTimeComparer();
myComparer.Compare(left, right);

Another way to do this would be to make an extension method for Nullable types whose values are comparable

public static class NullableComparableExtensions
{
    public static int CompareTo<T>(this T? left, T? right)
        where T : struct, IComparable<T>
    {
        return left.GetValueOrDefault().CompareTo(right.GetValueOrDefault());
    }
}

Where you'd use it like this

DateTime? left = null, right = DateTime.Now;
left.CompareTo(right);