Count< TSource >() [1/2]

static int System.Linq.Enumerable.Count< TSource > ( this IEnumerable< TSource > source )

inlinestatic

Definition at line 4435 of file Enumerable.cs.

    {
        if (source == null)
        {
            ThrowHelper.ThrowArgumentNullException(ExceptionArgument.source);
        }
        if (source is ICollection<TSource> collection)
        {
            return collection.Count;
        }
        if (source is IIListProvider<TSource> iIListProvider)
        {
            return iIListProvider.GetCount(onlyIfCheap: false);
        }
        if (source is ICollection collection2)
        {
            return collection2.Count;
        }
        int num = 0;
        using IEnumerator<TSource> enumerator = source.GetEnumerator();
        while (enumerator.MoveNext())
        {
            num = checked(num + 1);
        }
        return num;
    }

References System.collection, System.Collections.Generic.Dictionary< TKey, TValue >.Count, System.Collections.Generic.Dictionary< TKey, TValue >.GetEnumerator(), System.Linq.source, and System.Linq.ThrowHelper.ThrowArgumentNullException().