Int Array Null Foreach Int Iin Array Enumerable Empty Lt Int Gt 2818164

int[] array=null; foreach(int iin array??Enumerable.Empty()) { System.Console.WriteLine(string.Format(“{0}”, i)); }

and

int[] returnArray=Do.Something()??newint[]{};

and

…??newint[0]

In a NotifyCollectionChangedEventHandler I wanted to apply the Enumerable.Empty like so:

foreach(DrawingPoint drawingPointin e.OldItems??Enumerable.Empty()) this.RemovePointMarker(drawingPoint);

Note: OldItems is of the type IList

And it gives me:

Operator ‘??’ cannot be applied to operands of type ‘System.Collections.IList’ and System.Collections.Generic.IEnumerable

However

foreach(DrawingPoint drawingPointin e.OldItems??newint[0])

and

foreach(DrawingPoint drawingPointin e.OldItems??newint[]{})

works just fine.

Why is that?
Why does IList ?? T[] work but IList ?? IEnumerable doesn’t?

Prof. Angela

4.6/5

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