I have a Unity game using WebGL and c#.
I am running Unity 2020.2.6f1, from what I understand is using c# 7.3
I currently check for null or empty arrays like this:
ObjectType[] myObjectTypeList = FindObjectsOfType<ObjectType>();
if(myObjectTypeList != null && myObjectTypeList.Length > 0)
{
...
}
But I read that in c# 7+ you can shorten to this:
if(!(myObjectTypeList?.Length != 0))
{
...
}
Is this something I can do in a Unity c# script when I am using FindObjectsOfType?
Thanks!
In C#7 C# 8.0 you can use the is operator and, your if statement could be
if (myObjectTypeList is {Length: > 0}){
// [...]
}
which is equal to
if (myObjectTypeList != null && myObjectTypeList.Length > 0){
// [...]
}
This answer is wrong.
According to Microsoft's Documentation:
Beginning with C# 8.0, you use a property pattern to match an expression's properties or fields against nested patterns [...]
This feature works only from c#8.0 and later. That said, this answer will still work, since Unity Version 2020.2 uses Roslyn Compiler with C# 8.0 Language Support.
is operator: This operator can do multiple things at the same time. Want to typecheck, cast, validate a member value and use an object at the same time? for: object myObjectTypeListAsObject could work like if (myObjectTypeListAsObject is ObjectType[] {Length: > 0} myObjectTypeList) { /*stuff with myObjectTypeList*/ }The ?. is called the Null Conditional Operator. a?.b will resolve to b, unless a is null, in which case it resolves to null. This operator was actually new since C# 6.0.
If you can live with the warnings you will get about calling an extension method on a null, this should work:
public static class Extensions
{
public static bool NotNullHasItems<T> (this IEnumerable<T> collection)
{
if (collection == null)
{
return false;
}
return collection.Any();
}
}
To test this, I used:
List<string> stuff = null;
var shouldBeFalse = stuff.NotNullHasItems();
stuff = new List<string>();
var shouldAlsoBeFalse = stuff.NotNullHasItems();
stuff.Add("test");
var shouldBeTrue = stuff.NotNullHasItems();
and both shouldBeFalse and shouldAlsoBeFalse ended up false while shouldBeTrue was true.
You may want a better name (perhaps reverse the logic and name it IsNullOrEmpty to match string.IsNullOrEmpty)
