Enumerable.ToDictionary 方法

定義

多載

ToDictionary<TKey,TValue>(IEnumerable<ValueTuple<TKey,TValue>>, IEqualityComparer<TKey>)

根據指定的索引鍵相等比較子,從列舉建立字典。

ToDictionary<TKey,TValue>(IEnumerable<KeyValuePair<TKey,TValue>>, IEqualityComparer<TKey>)

根據指定的索引鍵比較子,從列舉建立字典。

ToDictionary<TKey,TValue>(IEnumerable<KeyValuePair<TKey,TValue>>)

根據索引鍵類型的預設比較子,從列舉建立字典。

ToDictionary<TKey,TValue>(IEnumerable<ValueTuple<TKey,TValue>>)

根據索引鍵類型的預設比較子,從列舉建立字典。

ToDictionary<TSource,TKey,TElement>(IEnumerable<TSource>, Func<TSource,TKey>, Func<TSource,TElement>)

根據指定的索引鍵選取器和項目選取器函式,從 Dictionary<TKey,TValue> 建立 IEnumerable<T>

ToDictionary<TSource,TKey,TElement>(IEnumerable<TSource>, Func<TSource,TKey>, Func<TSource,TElement>, IEqualityComparer<TKey>)

根據指定的索引鍵選取器函式、比較子和項目選取器函式,從 Dictionary<TKey,TValue> 建立 IEnumerable<T>

ToDictionary<TSource,TKey>(IEnumerable<TSource>, Func<TSource,TKey>)

根據指定的索引鍵選擇器函式,從 Dictionary<TKey,TValue> 建立 IEnumerable<T>

ToDictionary<TSource,TKey>(IEnumerable<TSource>, Func<TSource,TKey>, IEqualityComparer<TKey>)

根據指定的索引鍵選取器函式和索引鍵比較子,從 Dictionary<TKey,TValue> 建立 IEnumerable<T>

ToDictionary<TKey,TValue>(IEnumerable<ValueTuple<TKey,TValue>>, IEqualityComparer<TKey>)

根據指定的索引鍵相等比較子,從列舉建立字典。

public:
generic <typename TKey, typename TValue>
[System::Runtime::CompilerServices::Extension]
 static System::Collections::Generic::Dictionary<TKey, TValue> ^ ToDictionary(System::Collections::Generic::IEnumerable<ValueTuple<TKey, TValue>> ^ source, System::Collections::Generic::IEqualityComparer<TKey> ^ comparer);
public static System.Collections.Generic.Dictionary<TKey,TValue> ToDictionary<TKey,TValue> (this System.Collections.Generic.IEnumerable<(TKey Key, TValue Value)> source, System.Collections.Generic.IEqualityComparer<TKey>? comparer);
static member ToDictionary : seq<ValueTuple<'Key, 'Value>> * System.Collections.Generic.IEqualityComparer<'Key> -> System.Collections.Generic.Dictionary<'Key, 'Value>
<Extension()>
Public Function ToDictionary(Of TKey, TValue) (source As IEnumerable(Of ValueTuple(Of TKey, TValue)), comparer As IEqualityComparer(Of TKey)) As Dictionary(Of TKey, TValue)

類型參數

TKey

元素 source 中的索引鍵型別。

TValue

專案 source 的值型別。

參數

source
IEnumerable<ValueTuple<TKey,TValue>>

要從中建立字典的列舉。

comparer
IEqualityComparer<TKey>

要比較索引鍵的相等比較子。

傳回

字典,包含 來自 source 的索引鍵和值。

例外狀況

sourcenull 參考。

source 包含一或多個重複的索引鍵。

備註

如果 comparernull ,則會使用預設相等比較子 Default 來比較索引鍵。

適用於

ToDictionary<TKey,TValue>(IEnumerable<KeyValuePair<TKey,TValue>>, IEqualityComparer<TKey>)

根據指定的索引鍵比較子,從列舉建立字典。

public:
generic <typename TKey, typename TValue>
[System::Runtime::CompilerServices::Extension]
 static System::Collections::Generic::Dictionary<TKey, TValue> ^ ToDictionary(System::Collections::Generic::IEnumerable<System::Collections::Generic::KeyValuePair<TKey, TValue>> ^ source, System::Collections::Generic::IEqualityComparer<TKey> ^ comparer);
public static System.Collections.Generic.Dictionary<TKey,TValue> ToDictionary<TKey,TValue> (this System.Collections.Generic.IEnumerable<System.Collections.Generic.KeyValuePair<TKey,TValue>> source, System.Collections.Generic.IEqualityComparer<TKey>? comparer);
static member ToDictionary : seq<System.Collections.Generic.KeyValuePair<'Key, 'Value>> * System.Collections.Generic.IEqualityComparer<'Key> -> System.Collections.Generic.Dictionary<'Key, 'Value>
<Extension()>
Public Function ToDictionary(Of TKey, TValue) (source As IEnumerable(Of KeyValuePair(Of TKey, TValue)), comparer As IEqualityComparer(Of TKey)) As Dictionary(Of TKey, TValue)

類型參數

TKey

元素 source 中的索引鍵型別。

TValue

專案 source 的值型別。

參數

source
IEnumerable<KeyValuePair<TKey,TValue>>

要從中建立字典的列舉。

comparer
IEqualityComparer<TKey>

要比較索引鍵的相等比較子。

傳回

字典,包含 來自 source 的索引鍵和值。

例外狀況

sourcenull 參考。

source 包含一或多個重複的索引鍵。

備註

如果 comparernull ,則會使用預設相等比較子 Default 來比較索引鍵。

適用於

ToDictionary<TKey,TValue>(IEnumerable<KeyValuePair<TKey,TValue>>)

根據索引鍵類型的預設比較子,從列舉建立字典。

public:
generic <typename TKey, typename TValue>
[System::Runtime::CompilerServices::Extension]
 static System::Collections::Generic::Dictionary<TKey, TValue> ^ ToDictionary(System::Collections::Generic::IEnumerable<System::Collections::Generic::KeyValuePair<TKey, TValue>> ^ source);
public static System.Collections.Generic.Dictionary<TKey,TValue> ToDictionary<TKey,TValue> (this System.Collections.Generic.IEnumerable<System.Collections.Generic.KeyValuePair<TKey,TValue>> source);
static member ToDictionary : seq<System.Collections.Generic.KeyValuePair<'Key, 'Value>> -> System.Collections.Generic.Dictionary<'Key, 'Value>
<Extension()>
Public Function ToDictionary(Of TKey, TValue) (source As IEnumerable(Of KeyValuePair(Of TKey, TValue))) As Dictionary(Of TKey, TValue)

類型參數

TKey

元素 source 中的索引鍵型別。

TValue

專案 source 的值型別。

參數

source
IEnumerable<KeyValuePair<TKey,TValue>>

要從中建立字典的列舉。

傳回

包含索引 source 鍵和值的字典,並使用索引鍵類型的預設比較子。

例外狀況

sourcenull 參考。

source 包含一或多個重複的索引鍵。

適用於

ToDictionary<TKey,TValue>(IEnumerable<ValueTuple<TKey,TValue>>)

根據索引鍵類型的預設比較子,從列舉建立字典。

public:
generic <typename TKey, typename TValue>
[System::Runtime::CompilerServices::Extension]
 static System::Collections::Generic::Dictionary<TKey, TValue> ^ ToDictionary(System::Collections::Generic::IEnumerable<ValueTuple<TKey, TValue>> ^ source);
public static System.Collections.Generic.Dictionary<TKey,TValue> ToDictionary<TKey,TValue> (this System.Collections.Generic.IEnumerable<(TKey Key, TValue Value)> source);
static member ToDictionary : seq<ValueTuple<'Key, 'Value>> -> System.Collections.Generic.Dictionary<'Key, 'Value>
<Extension()>
Public Function ToDictionary(Of TKey, TValue) (source As IEnumerable(Of ValueTuple(Of TKey, TValue))) As Dictionary(Of TKey, TValue)

類型參數

TKey

元素 source 中的索引鍵型別。

TValue

專案 source 的值型別。

參數

source
IEnumerable<ValueTuple<TKey,TValue>>

要從中建立字典的列舉。

傳回

包含索引 source 鍵和值的字典,並使用索引鍵類型的預設比較子。

例外狀況

sourcenull 參考。

source 包含一或多個重複的索引鍵。

適用於

ToDictionary<TSource,TKey,TElement>(IEnumerable<TSource>, Func<TSource,TKey>, Func<TSource,TElement>)

根據指定的索引鍵選取器和項目選取器函式,從 Dictionary<TKey,TValue> 建立 IEnumerable<T>

public:
generic <typename TSource, typename TKey, typename TElement>
[System::Runtime::CompilerServices::Extension]
 static System::Collections::Generic::Dictionary<TKey, TElement> ^ ToDictionary(System::Collections::Generic::IEnumerable<TSource> ^ source, Func<TSource, TKey> ^ keySelector, Func<TSource, TElement> ^ elementSelector);
public static System.Collections.Generic.Dictionary<TKey,TElement> ToDictionary<TSource,TKey,TElement> (this System.Collections.Generic.IEnumerable<TSource> source, Func<TSource,TKey> keySelector, Func<TSource,TElement> elementSelector);
static member ToDictionary : seq<'Source> * Func<'Source, 'Key> * Func<'Source, 'Element> -> System.Collections.Generic.Dictionary<'Key, 'Element>
<Extension()>
Public Function ToDictionary(Of TSource, TKey, TElement) (source As IEnumerable(Of TSource), keySelector As Func(Of TSource, TKey), elementSelector As Func(Of TSource, TElement)) As Dictionary(Of TKey, TElement)

類型參數

TSource

source 項目的類型。

TKey

keySelector 所傳回之索引鍵的型別。

TElement

elementSelector 所傳回值的型別。

參數

source
IEnumerable<TSource>

用來建立 Dictionary<TKey,TValue> 的來源 IEnumerable<T>

keySelector
Func<TSource,TKey>

用來從各個項目擷取索引鍵的函式。

elementSelector
Func<TSource,TElement>

用來從每個項目產生結果項目值的轉換函式。

傳回

Dictionary<TKey,TElement>

Dictionary<TKey,TValue>,包含從輸入序列選取之 TElement 類型的值。

例外狀況

sourcekeySelectorelementSelectornull

-或-

keySelector 產生的索引鍵為 null

keySelector 產生兩個項目的重複索引鍵。

備註

方法 ToDictionary<TSource,TKey,TElement>(IEnumerable<TSource>, Func<TSource,TKey>, Func<TSource,TElement>) 會使用預設相等比較子 Default 來比較索引鍵。

適用於

ToDictionary<TSource,TKey,TElement>(IEnumerable<TSource>, Func<TSource,TKey>, Func<TSource,TElement>, IEqualityComparer<TKey>)

根據指定的索引鍵選取器函式、比較子和項目選取器函式,從 Dictionary<TKey,TValue> 建立 IEnumerable<T>

public:
generic <typename TSource, typename TKey, typename TElement>
[System::Runtime::CompilerServices::Extension]
 static System::Collections::Generic::Dictionary<TKey, TElement> ^ ToDictionary(System::Collections::Generic::IEnumerable<TSource> ^ source, Func<TSource, TKey> ^ keySelector, Func<TSource, TElement> ^ elementSelector, System::Collections::Generic::IEqualityComparer<TKey> ^ comparer);
public static System.Collections.Generic.Dictionary<TKey,TElement> ToDictionary<TSource,TKey,TElement> (this System.Collections.Generic.IEnumerable<TSource> source, Func<TSource,TKey> keySelector, Func<TSource,TElement> elementSelector, System.Collections.Generic.IEqualityComparer<TKey> comparer);
public static System.Collections.Generic.Dictionary<TKey,TElement> ToDictionary<TSource,TKey,TElement> (this System.Collections.Generic.IEnumerable<TSource> source, Func<TSource,TKey> keySelector, Func<TSource,TElement> elementSelector, System.Collections.Generic.IEqualityComparer<TKey>? comparer);
static member ToDictionary : seq<'Source> * Func<'Source, 'Key> * Func<'Source, 'Element> * System.Collections.Generic.IEqualityComparer<'Key> -> System.Collections.Generic.Dictionary<'Key, 'Element>
<Extension()>
Public Function ToDictionary(Of TSource, TKey, TElement) (source As IEnumerable(Of TSource), keySelector As Func(Of TSource, TKey), elementSelector As Func(Of TSource, TElement), comparer As IEqualityComparer(Of TKey)) As Dictionary(Of TKey, TElement)

類型參數

TSource

source 項目的類型。

TKey

keySelector 所傳回之索引鍵的型別。

TElement

elementSelector 所傳回值的型別。

參數

source
IEnumerable<TSource>

用來建立 Dictionary<TKey,TValue> 的來源 IEnumerable<T>

keySelector
Func<TSource,TKey>

用來從各個項目擷取索引鍵的函式。

elementSelector
Func<TSource,TElement>

用來從每個項目產生結果項目值的轉換函式。

comparer
IEqualityComparer<TKey>

用來比較金鑰的 IEqualityComparer<T>

傳回

Dictionary<TKey,TElement>

Dictionary<TKey,TValue>,包含從輸入序列選取之 TElement 類型的值。

例外狀況

sourcekeySelectorelementSelectornull

-或-

keySelector 產生的索引鍵為 null

keySelector 產生兩個項目的重複索引鍵。

備註

如果 comparernull ,則會使用預設相等比較子 Default 來比較索引鍵。

適用於

ToDictionary<TSource,TKey>(IEnumerable<TSource>, Func<TSource,TKey>)

根據指定的索引鍵選擇器函式,從 Dictionary<TKey,TValue> 建立 IEnumerable<T>

public:
generic <typename TSource, typename TKey>
[System::Runtime::CompilerServices::Extension]
 static System::Collections::Generic::Dictionary<TKey, TSource> ^ ToDictionary(System::Collections::Generic::IEnumerable<TSource> ^ source, Func<TSource, TKey> ^ keySelector);
public static System.Collections.Generic.Dictionary<TKey,TSource> ToDictionary<TSource,TKey> (this System.Collections.Generic.IEnumerable<TSource> source, Func<TSource,TKey> keySelector);
static member ToDictionary : seq<'Source> * Func<'Source, 'Key> -> System.Collections.Generic.Dictionary<'Key, 'Source>
<Extension()>
Public Function ToDictionary(Of TSource, TKey) (source As IEnumerable(Of TSource), keySelector As Func(Of TSource, TKey)) As Dictionary(Of TKey, TSource)

類型參數

TSource

source 項目的類型。

TKey

keySelector 所傳回之索引鍵的型別。

參數

source
IEnumerable<TSource>

用來建立 Dictionary<TKey,TValue> 的來源 IEnumerable<T>

keySelector
Func<TSource,TKey>

用來從各個項目擷取索引鍵的函式。

傳回

Dictionary<TKey,TSource>

包含索引鍵和值的 Dictionary<TKey,TValue>。 每個群組中的值與 source 中的順序相同。

例外狀況

sourcekeySelectornull

-或-

keySelector 產生的索引鍵為 null

keySelector 產生兩個項目的重複索引鍵。

範例

下列程式碼範例示範如何使用 ToDictionary<TSource,TKey>(IEnumerable<TSource>, Func<TSource,TKey>) 索引鍵選取器來建立 Dictionary<TKey,TValue>

class Package
{
    public string Company { get; set; }
    public double Weight { get; set; }
    public long TrackingNumber { get; set; }
}

public static void ToDictionaryEx1()
{
    List<Package> packages =
        new List<Package>
            { new Package { Company = "Coho Vineyard", Weight = 25.2, TrackingNumber = 89453312L },
              new Package { Company = "Lucerne Publishing", Weight = 18.7, TrackingNumber = 89112755L },
              new Package { Company = "Wingtip Toys", Weight = 6.0, TrackingNumber = 299456122L },
              new Package { Company = "Adventure Works", Weight = 33.8, TrackingNumber = 4665518773L } };

    // Create a Dictionary of Package objects,
    // using TrackingNumber as the key.
    Dictionary<long, Package> dictionary =
        packages.ToDictionary(p => p.TrackingNumber);

    foreach (KeyValuePair<long, Package> kvp in dictionary)
    {
        Console.WriteLine(
            "Key {0}: {1}, {2} pounds",
            kvp.Key,
            kvp.Value.Company,
            kvp.Value.Weight);
    }
}

/*
 This code produces the following output:

 Key 89453312: Coho Vineyard, 25.2 pounds
 Key 89112755: Lucerne Publishing, 18.7 pounds
 Key 299456122: Wingtip Toys, 6 pounds
 Key 4665518773: Adventure Works, 33.8 pounds
*/
Structure Package
    Public Company As String
    Public Weight As Double
    Public TrackingNumber As Long
End Structure

Sub ToDictionaryEx1()
    ' Create a list of Package values.
    Dim packages As New List(Of Package)(New Package() _
     {New Package With
      {.Company = "Coho Vineyard", .Weight = 25.2, .TrackingNumber = 89453312L},
      New Package With
      {.Company = "Lucerne Publishing", .Weight = 18.7, .TrackingNumber = 89112755L},
      New Package With
      {.Company = "Wingtip Toys", .Weight = 6.0, .TrackingNumber = 299456122L},
      New Package With
      {.Company = "Adventure Works", .Weight = 33.8, .TrackingNumber = 4665518773L}})

    ' Create a Dictionary that contains Package values,
    ' using TrackingNumber as the key.
    Dim dict As Dictionary(Of Long, Package) =
    packages.ToDictionary(Function(p) p.TrackingNumber)

    ' Display the results.
    Dim output As New System.Text.StringBuilder
    For Each kvp As KeyValuePair(Of Long, Package) In dict
        output.AppendLine("Key " & kvp.Key & ": " &
                      kvp.Value.Company & ", " &
                      kvp.Value.Weight & " pounds")
    Next
    Console.WriteLine(output.ToString())
End Sub

' This code produces the following output:
'
' Key 89453312: Coho Vineyard, 25.2 pounds
' Key 89112755: Lucerne Publishing, 18.7 pounds
' Key 299456122: Wingtip Toys, 6 pounds
' Key 4665518773: Adventure Works, 33.8 pounds

備註

方法 ToDictionary<TSource,TKey>(IEnumerable<TSource>, Func<TSource,TKey>) 會使用預設相等比較子 Default 來比較索引鍵。

適用於

ToDictionary<TSource,TKey>(IEnumerable<TSource>, Func<TSource,TKey>, IEqualityComparer<TKey>)

根據指定的索引鍵選取器函式和索引鍵比較子,從 Dictionary<TKey,TValue> 建立 IEnumerable<T>

public:
generic <typename TSource, typename TKey>
[System::Runtime::CompilerServices::Extension]
 static System::Collections::Generic::Dictionary<TKey, TSource> ^ ToDictionary(System::Collections::Generic::IEnumerable<TSource> ^ source, Func<TSource, TKey> ^ keySelector, System::Collections::Generic::IEqualityComparer<TKey> ^ comparer);
public static System.Collections.Generic.Dictionary<TKey,TSource> ToDictionary<TSource,TKey> (this System.Collections.Generic.IEnumerable<TSource> source, Func<TSource,TKey> keySelector, System.Collections.Generic.IEqualityComparer<TKey> comparer);
public static System.Collections.Generic.Dictionary<TKey,TSource> ToDictionary<TSource,TKey> (this System.Collections.Generic.IEnumerable<TSource> source, Func<TSource,TKey> keySelector, System.Collections.Generic.IEqualityComparer<TKey>? comparer);
static member ToDictionary : seq<'Source> * Func<'Source, 'Key> * System.Collections.Generic.IEqualityComparer<'Key> -> System.Collections.Generic.Dictionary<'Key, 'Source>
<Extension()>
Public 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)

類型參數

TSource

source 項目的類型。

TKey

keySelector 所傳回之索引鍵的型別。

參數

source
IEnumerable<TSource>

用來建立 Dictionary<TKey,TValue> 的來源 IEnumerable<T>

keySelector
Func<TSource,TKey>

用來從各個項目擷取索引鍵的函式。

comparer
IEqualityComparer<TKey>

用來比較金鑰的 IEqualityComparer<T>

傳回

Dictionary<TKey,TSource>

包含索引鍵和值的 Dictionary<TKey,TValue>。 每個群組中的值與 source 中的順序相同。

例外狀況

sourcekeySelectornull

-或-

keySelector 產生的索引鍵為 null

keySelector 產生兩個項目的重複索引鍵。

備註

如果 comparernull ,則會使用預設相等比較子 Default 來比較索引鍵。

適用於