ParallelEnumerable::ToDictionary<TSource, TKey, TElement> Method (ParallelQuery<TSource>^, Func<TSource, TKey>^, Func<TSource, TElement>^, IEqualityComparer<TKey>^)
Creates a Dictionary<TKey, TValue> from a ParallelQuery<TSource> according to a specified key selector function, a comparer, and an element selector function.
Assembly: System.Core (in System.Core.dll)
public: generic<typename TSource, typename TKey, typename TElement> [ExtensionAttribute] static Dictionary<TKey, TElement>^ ToDictionary( ParallelQuery<TSource>^ source, Func<TSource, TKey>^ keySelector, Func<TSource, TElement>^ elementSelector, IEqualityComparer<TKey>^ comparer )
Parameters
- source
-
Type:
System.Linq::ParallelQuery<TSource>^
A sequence to create a Dictionary<TKey, TValue> from.
- keySelector
-
Type:
System::Func<TSource, TKey>^
A function to extract a key from each element.
- elementSelector
-
Type:
System::Func<TSource, TElement>^
A transform function to produce a result element value from each element.
- comparer
-
Type:
System.Collections.Generic::IEqualityComparer<TKey>^
An IEqualityComparer<T> to compare keys.
Return Value
Type: System.Collections.Generic::Dictionary<TKey, TElement>^A Dictionary<TKey, TValue> that contains values of type TElement selected from the input sequence
Type Parameters
- TSource
The type of the elements of source.
- TKey
The type of the key returned by keySelector.
- TElement
The type of the value returned by elementSelector.
| Exception | Condition |
|---|---|
| OperationCanceledException | The query was canceled with the token passed in through WithCancellation. |
| ArgumentNullException | source or keySelector or elementSelector is a null reference (Nothing in Visual Basic). |
| AggregateException | keySelector produces a key that is a null reference (Nothing in Visual Basic). -or- keySelector produces duplicate keys for two elements. -or- One or more exceptions occurred during the evaluation of the query. |
Available since 8
.NET Framework
Available since 4.0
Portable Class Library
Supported in: portable .NET platforms
Windows Phone
Available since 8.1