ToDictionary< TSource, TKey >() [3/4]

static Dictionary< TKey, TSource > System.Linq.Enumerable.ToDictionary< TSource, TKey > ( this IEnumerable< TSource > source, Func< TSource, TKey > keySelector, IEqualityComparer< TKey >? comparer )

inlinestatic

Type Constraints

TKey

:

notnull

Definition at line 8320 of file Enumerable.cs.

                                                                                                                                                                                         : notnull
    {
        if (source == null)
        {
            ThrowHelper.ThrowArgumentNullException(ExceptionArgument.source);
        }
        if (keySelector == null)
        {
            ThrowHelper.ThrowArgumentNullException(ExceptionArgument.keySelector);
        }
        int num = 0;
        if (source is ICollection<TSource> collection)
        {
            num = collection.Count;
            if (num == 0)
            {
                return new Dictionary<TKey, TSource>(comparer);
            }
            if (collection is TSource[] source2)
            {
                return ToDictionary(source2, keySelector, comparer);
            }
            if (collection is List<TSource> source3)
            {
                return ToDictionary<TSource, TKey>(source3, keySelector, comparer);
            }
        }
        Dictionary<TKey, TSource> dictionary = new Dictionary<TKey, TSource>(num, comparer);
        foreach (TSource item in source)
        {
            dictionary.Add(keySelector(item), item);
        }
        return dictionary;
    }

References System.collection, System.comparer, System.dictionary, System.item, System.Linq.keySelector, System.Linq.source, System.Linq.ThrowHelper.ThrowArgumentNullException(), and System.Linq.Enumerable.ToDictionary< TSource, TKey >().