What is the minimum interface that has the Count property in .Net

I need to change开发者_如何学Go a method that has one parameter that takes a serie of objects. I need to find the lowest Interface (in inheritance tree) that has the Count property. Until now I was using the IEnumerable but as this has not Count I need to change it to the wider interface possible so the method can work with the biggest number of types of series (collections, lists, arrays, etc).

Thanks in advance.

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ICollection adds the Count property.

As @Joren rightly points point, IEnumerable<T> has the extension method Count<T>() if you're happy making your collection generic. However, as @Joel Coehoorn has pointed out, it is inadvisable to use this as it forces an iteration of the sequence.

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ICollection adds the Count property.

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System.Collections.ICollection, and also System.Collections.Generic.ICollection<T>. These two interfaces have no relation to eachother, but both inherit from IEnumerable, so they're at the same level.

IEnumerable obviously does not have a Count property (the count isn't necessarily predetermined).