Enumerable::ToDictionary<TSource, TKey> Method (IEnumerable<TSource>^, Func<TSource, TKey>^)
Creates a Dictionary<TKey, TValue> from an IEnumerable<T> according to a specified key selector function.
Assembly: System.Core (in System.Core.dll)
public: generic<typename TSource, typename TKey> [ExtensionAttribute] static Dictionary<TKey, TSource>^ ToDictionary( IEnumerable<TSource>^ source, Func<TSource, TKey>^ keySelector )
Parameters
- source
-
Type:
System.Collections.Generic::IEnumerable<TSource>^
An IEnumerable<T> to create a Dictionary<TKey, TValue> from.
- keySelector
-
Type:
System::Func<TSource, TKey>^
A function to extract a key from each element.
Return Value
Type: System.Collections.Generic::Dictionary<TKey, TSource>^A Dictionary<TKey, TValue> that contains keys and values.
Type Parameters
- TSource
The type of the elements of source.
- TKey
The type of the key returned by keySelector.
| Exception | Condition |
|---|---|
| ArgumentNullException | source or keySelector is null. -or- keySelector produces a key that is null. |
| ArgumentException | keySelector produces duplicate keys for two elements. |
The ToDictionary<TSource, TKey>(IEnumerable<TSource>^, Func<TSource, TKey>^) method uses the default equality comparer Default to compare keys.
The following code example demonstrates how to use ToDictionary<TSource, TKey>(IEnumerable<TSource>^, Func<TSource, TKey>^) to create a Dictionary<TKey, TValue> by using a key selector.
Available since 8
.NET Framework
Available since 3.5
Portable Class Library
Supported in: portable .NET platforms
Silverlight
Available since 2.0
Windows Phone Silverlight
Available since 7.0
Windows Phone
Available since 8.1