C# Nullable<DateTime> to string

Though many of these answers are correct, all of them are needlessly complex. The result of calling ToString on a nullable DateTime is already an empty string if the value is logically null. Just call ToString on your value; it will do exactly what you want.

string date = myVariable.HasValue ? myVariable.Value.ToString() : string.Empty;

Actually, this is the default behaviour for Nullable types, that without a value they return nothing:

public class Test {
    public static void Main() {
        System.DateTime? dt = null;
        System.Console.WriteLine("<{0}>", dt.ToString());
        dt = System.DateTime.Now;
        System.Console.WriteLine("<{0}>", dt.ToString());
    }
}

this yields

<>
<2009-09-18 19:16:09>