.NET Framework Class Library
EnumerableToDictionaryTSource, TKey, TElement Method (IEnumerableTSource, FuncTSource, TKey, FuncTSource, TElement, IEqualityComparerTKey)

Creates a DictionaryTKey, TValue from an IEnumerableT according to a specified key selector function, a comparer, and an element selector function.

Namespace:   System.Linq
Assembly:  System.Core (in System.Core.dll)
Syntax
<[%$TOPIC/bb548652_en-us_VS_110_3_0_0_0_0%]> _
Public Shared Function ToDictionary(Of TSource, TKey, TElement) ( _
	source As [%$TOPIC/bb548652_en-us_VS_110_3_0_0_0_1%](Of TSource), _
	keySelector As [%$TOPIC/bb548652_en-us_VS_110_3_0_0_0_2%](Of TSource, TKey), _
	elementSelector As [%$TOPIC/bb548652_en-us_VS_110_3_0_0_0_3%](Of TSource, TElement), _
	comparer As [%$TOPIC/bb548652_en-us_VS_110_3_0_0_0_4%](Of TKey) _
) As [%$TOPIC/bb548652_en-us_VS_110_3_0_0_0_5%](Of TKey, TElement)
public static [%$TOPIC/bb548652_en-us_VS_110_3_0_1_0_0%]<TKey, TElement> ToDictionary<TSource, TKey, TElement>(
	this [%$TOPIC/bb548652_en-us_VS_110_3_0_1_0_1%]<TSource> source,
	[%$TOPIC/bb548652_en-us_VS_110_3_0_1_0_2%]<TSource, TKey> keySelector,
	[%$TOPIC/bb548652_en-us_VS_110_3_0_1_0_3%]<TSource, TElement> elementSelector,
	[%$TOPIC/bb548652_en-us_VS_110_3_0_1_0_4%]<TKey> comparer
)
[[%$TOPIC/bb548652_en-us_VS_110_3_0_2_0_0%]]
public:
generic<typename TSource, typename TKey, typename TElement>
static [%$TOPIC/bb548652_en-us_VS_110_3_0_2_0_1%]<TKey, TElement>^ ToDictionary(
	[%$TOPIC/bb548652_en-us_VS_110_3_0_2_0_2%]<TSource>^ source, 
	[%$TOPIC/bb548652_en-us_VS_110_3_0_2_0_3%]<TSource, TKey>^ keySelector, 
	[%$TOPIC/bb548652_en-us_VS_110_3_0_2_0_4%]<TSource, TElement>^ elementSelector, 
	[%$TOPIC/bb548652_en-us_VS_110_3_0_2_0_5%]<TKey>^ comparer
)
static member ToDictionary : 
        source:[%$TOPIC/bb548652_en-us_VS_110_3_0_3_0_0%]<'TSource> * 
        keySelector:[%$TOPIC/bb548652_en-us_VS_110_3_0_3_0_1%]<'TSource, 'TKey> * 
        elementSelector:[%$TOPIC/bb548652_en-us_VS_110_3_0_3_0_2%]<'TSource, 'TElement> * 
        comparer:[%$TOPIC/bb548652_en-us_VS_110_3_0_3_0_3%]<'TKey> -> [%$TOPIC/bb548652_en-us_VS_110_3_0_3_0_4%]<'TKey, 'TElement> 
JScript does not support generic types or methods.

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.

Parameters

source
Type: System.Collections.GenericIEnumerableTSource

An IEnumerableT to create a DictionaryTKey, TValue from.

keySelector
Type: SystemFuncTSource, TKey

A function to extract a key from each element.

elementSelector
Type: SystemFuncTSource, TElement

A transform function to produce a result element value from each element.

comparer
Type: System.Collections.GenericIEqualityComparerTKey

An IEqualityComparerT to compare keys.

Return Value

Type: System.Collections.GenericDictionaryTKey, TElement
A DictionaryTKey, TValue that contains values of type TElement selected from the input sequence.

Usage Note

In Visual Basic and C#, you can call this method as an instance method on any object of type IEnumerableTSource. When you use instance method syntax to call this method, omit the first parameter. For more information, see Extension Methods (Visual Basic) or Extension Methods (C# Programming Guide).
Exceptions
ExceptionCondition
ArgumentNullException

source or keySelector or elementSelector is .

-or-

keySelector produces a key that is .

ArgumentException

keySelector produces duplicate keys for two elements.

Remarks

If comparer is , the default equality comparer Default is used to compare keys.

Version Information

.NET Framework

Supported in: 4.6, 4.5, 4, 3.5

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

XNA Framework

Supported in: 3.0

Portable Class Library

Supported in: Portable Class Library

Supported in: Windows Phone 8.1

Supported in: Windows Phone Silverlight 8.1

Supported in: Windows Phone Silverlight 8