CODEWITHSUNDEEP
c#genericsparameters
Jake
Jake

Reputation: 7782

Overloading a params function with an IEnumerable

Suppose I have two functions:

Foo(params INotifyPropertyChanged[] items)
{
   //do stuff
}

Foo<T>(IEnumerable<T> items) where T : INotifyPropertyChanged
{
   Foo(items.ToArray());
}

The second one allows me to call Foo from a generic class with the constraint where T : INotifyPropertyChanged, but the second resolves to itself so I get a stack overflow exception.

  1. Is it possible to specify which overload I want to call when there's some ambiguity?
  2. Is there another way to call a params function from a generic class, assuming the generic type's constraints make it a viable option for the params type?

Thanks in advance!

Upvotes: 4

Views: 2754

Answers (2)

SLaks
SLaks

Reputation: 887867

You need to pass a INotifyPropertyChanged[], not a T[].
For example:

Foo<T>(IEnumerable<T> items) where T : INotifyPropertyChanged
{
   Foo(items.Cast<INotifyPropertyChanged>().ToArray());
}

In general, however, it's better to call the IEnumerable version from the params version, like this:

Foo(params INotifyPropertyChanged[] items)
{
   Foo((IEnumerable<INotifyPropertyChanged>) items);
}

Foo<T>(IEnumerable<T> items) where T : INotifyPropertyChanged
{
   //do stuff
}

Upvotes: 7

Femaref
Femaref

Reputation: 61477

You could try casting the input.

Foo<T>(IEnumerable<T> items) where T : INotifyPropertyChanged
{
   Foo(items.Cast<INotifyPropertyChanged>().ToArray());
}

If this doesn't work, I don't have an idea, you are probably out of luck.

Upvotes: 3

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