public static IEnumerable <TResult> GroupJoin <TKey, TSource, TInner, TResult>(this IndexDefinition <TSource> source,
IEnumerable <TInner> inner, Func <TInner, TKey> innerKeySelector,
Expression <Func <TSource, TKey> > outerKeySelector,
Func <TSource, IEnumerable <TInner>, TResult> resultSelector,
IEqualityComparer <TKey> equalityComparer)
{
Dictionary <TKey, Tuple <TSource, List <TInner> > > dictionary = new Dictionary <TKey, Tuple <TSource, List <TInner> > >();
foreach (TInner innerItem in inner)
{
TKey key = innerKeySelector(innerItem);
var value = IndexFinder.FindInIndex(source, outerKeySelector, key, equalityComparer);
if (value != null)
{
if (dictionary.ContainsKey(key))
{
Tuple <TSource, List <TInner> > tuple = dictionary[key];
tuple.Item2.Add(innerItem);
}
else
{
List <TInner> list = new List <TInner>();
list.Add(innerItem);
dictionary.Add(key, new Tuple <TSource, List <TInner> >(value, list));
}
}
}
foreach (KeyValuePair <TKey, Tuple <TSource, List <TInner> > > key in dictionary)
{
yield return(resultSelector(key.Value.Item1, key.Value.Item2));
}
}
public static IEnumerable <TResult> Join <TKey, TSource, TInner, TResult>(this IndexDefinition <TSource> source,
IEnumerable <TInner> inner, Func <TInner, TKey> innerKeySelector,
Expression <Func <TSource, TKey> > outerKeySelector,
Func <TSource, TInner, TResult> resultSelector)
{
foreach (TInner innerItem in inner)
{
TKey key = innerKeySelector(innerItem);
var value = IndexFinder.FindInIndex(source, outerKeySelector, key, null);
if (value != null)
{
yield return(resultSelector(value, innerItem));
}
}
}
