Enumerable.ToDictionary(Of TSource, TKey) Method (IEnumerable(Of TSource), Func(Of TSource, TKey), IEqualityComparer(Of TKey))
.NET Framework (current version)
Creates a Dictionary(Of TKey, TValue) from an IEnumerable(Of T) according to a specified key selector function and key comparer.
Assembly: System.Core (in System.Core.dll)
<ExtensionAttribute> Public Shared Function ToDictionary(Of TSource, TKey) ( source As IEnumerable(Of TSource), keySelector As Func(Of TSource, TKey), comparer As IEqualityComparer(Of TKey) ) As Dictionary(Of TKey, TSource)
Parameters
- source
-
Type:
System.Collections.Generic.IEnumerable(Of TSource)
An IEnumerable(Of T) to create a Dictionary(Of TKey, TValue) from.
- keySelector
-
Type:
System.Func(Of TSource, TKey)
A function to extract a key from each element.
- comparer
-
Type:
System.Collections.Generic.IEqualityComparer(Of TKey)
An IEqualityComparer(Of T) to compare keys.
Return Value
Type: System.Collections.Generic.Dictionary(Of TKey, TSource)A Dictionary(Of 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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