I'm trying to write a generic extension method that let's me do this:
this.startDate = startDateXAttribute.NullOrPropertyOf<DateTime>(() =>
{
return DateTime.Parse(startDateXAttribute.Value);
});
NullOrPropertyOf()
would return null
if it's used on a null
object (e.g. if startDateXAttribute
was null
), or return the result of a Func
if it's not null.
What would this extension method look like?
There's no short form for that; implementing one is a fairly frequently requested feature. The syntax could be something like:
x = foo.?bar.?baz;
That is, x is null if foo or foo.bar are null, and the result of foo.bar.baz if none of them are null.
We considered it for C# 4 but it did not make it anywhere near the top of the priority list. We'll keep it in mind for hypothetical future versions of the language.
UPDATE: C# 6 will have this feature. See http://roslyn.codeplex.com/discussions/540883 for a discussion of the design considerations.
The XAttribute Class provides an explicit conversion operator for this:
XAttribute startDateXAttribute = // ...
DateTime? result = (DateTime?)startDateXAttribute;
For the general case, the best option is probably this:
DateTime? result = (obj != null) ? (DateTime?)obj.DateTimeValue : null;
If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
Donate Us With