Enumerable.ToDictionary<TSource, TKey, TElement> Method (IEnumerable<TSource>, Func<TSource, TKey>, Func<TSource, TElement>)
Creates a Dictionary<TKey, TValue> from an IEnumerable<T> according to specified key selector and element selector functions.
Assembly: System.Core (in System.Core.dll)
public static Dictionary<TKey, TElement> ToDictionary<TSource, TKey, TElement>( this IEnumerable<TSource> source, Func<TSource, TKey> keySelector, Func<TSource, TElement> elementSelector )
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.
- elementSelector
-
Type:
System.Func<TSource, TElement>
A transform function to produce a result element value from each element.
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 |
|---|---|
| ArgumentNullException | source or keySelector or elementSelector is null. -or- keySelector produces a key that is null. |
| ArgumentException | keySelector produces duplicate keys for two elements. |
The ToDictionary<TSource, TKey, TElement>(IEnumerable<TSource>, Func<TSource, TKey>, Func<TSource, TElement>) method uses the default equality comparer Default to compare keys.
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