Enumerable.ToDictionary<TSource, TKey> Method (IEnumerable<TSource>, Func<TSource, TKey>, IEqualityComparer<TKey>)
.NET Framework (current version)
Creates a Dictionary<TKey, TValue> from an IEnumerable<T> according to a specified key selector function and key comparer.
Assembly: System.Core (in System.Core.dll)
public static Dictionary<TKey, TSource> ToDictionary<TSource, TKey>( this IEnumerable<TSource> source, Func<TSource, TKey> keySelector, IEqualityComparer<TKey> comparer )
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.
- comparer
-
Type:
System.Collections.Generic.IEqualityComparer<TKey>
An IEqualityComparer<T> to compare keys.
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 keys 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. |
Universal Windows Platform
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
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
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