c# - How do I use DateTime.TryParse with a Nullable<DateTime>?

Question

I want to use the DateTime.TryParse method to get the datetime value of a string into a Nullable. But when I try this:

DateTime? d;
bool success = DateTime.TryParse("some date text", out (DateTime)d);

the compiler tells me

'out' argument is not classified as a variable

Not sure what I need to do here. I've also tried:

out (DateTime)d.Value 

and that doesn't work either. Any ideas?

Answer 1

As Jason says, you can create a variable of the right type and pass that. You might want to encapsulate it in your own method:

public static DateTime? TryParse(string text)
{
    DateTime date;
    if (DateTime.TryParse(text, out date))
    {
        return date;
    }
    else
    {
        return null;
    }
}

... or if you like the conditional operator:

public static DateTime? TryParse(string text)
{
    DateTime date;
    return DateTime.TryParse(text, out date) ? date : (DateTime?) null;
}

Or in C# 7:

public static DateTime? TryParse(string text) =>
    DateTime.TryParse(text, out var date) ? date : (DateTime?) null;