Enumerable.ToDictionary 方法

定義

命名空間:: System.Linq

組件:: netstandard.dll, System.Linq.dll

組件:: System.Core.dll, System.Linq.dll

組件:: System.Linq.dll

組件:: System.Core.dll

組件:: netstandard.dll

重要

部分資訊涉及發行前產品，在發行之前可能會有大幅修改。 Microsoft 對此處提供的資訊，不做任何明確或隱含的瑕疵擔保。

從 Dictionary<TKey,TValue>建立 IEnumerable<T>。

多載

名稱	Description
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<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<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<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、比較子和元素選取器函式，從 Dictionary<TKey,TValue> 建立 IEnumerable<T>。
ToDictionary<TSource,TKey,TElement>(IEnumerable<TSource>, Func<TSource,TKey>, Func<TSource,TElement>)	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>(IEnumerable<TSource>, Func<TSource,TKey>)	根據指定的索引鍵選取器函式，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<KeyValuePair<TKey,TValue>>)

來源:: ToCollection.cs

來源:: ToCollection.cs

來源:: ToCollection.cs

來源:: ToCollection.cs

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

來自元素 source的鍵型。

TValue

來自元素 source的值類型。

參數

source: IEnumerable<KeyValuePair<TKey,TValue>>

列舉用來建立字典。

傳回

Dictionary<TKey,TValue>

一個包含鍵與值的 source 字典，並使用該鍵型別的預設比較器。

例外狀況

ArgumentNullException

source 是參考 null 。

ArgumentException

source 包含一個或多個重複鍵。

適用於

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

來源:: ToCollection.cs

來源:: ToCollection.cs

來源:: ToCollection.cs

來源:: ToCollection.cs

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

來自元素 source的鍵型。

TValue

來自元素 source的值類型。

參數

source: IEnumerable<ValueTuple<TKey,TValue>>

列舉用來建立字典。

傳回

Dictionary<TKey,TValue>

一個包含鍵與值的 source 字典，並使用預設比較器來管理鍵型別。

例外狀況

ArgumentNullException

source 是參考 null 。

ArgumentException

source 包含一個或多個重複鍵。

適用於

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

來源:: ToCollection.cs

來源:: ToCollection.cs

來源:: ToCollection.cs

來源:: ToCollection.cs

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

來自元素 source的鍵型。

TValue

來自元素 source的值類型。

參數

source: IEnumerable<KeyValuePair<TKey,TValue>>

列舉用來建立字典。

comparer: IEqualityComparer<TKey>

一個等式比較器來比較金鑰。

傳回

Dictionary<TKey,TValue>

一個包含鍵與值的 source字典。

例外狀況

ArgumentNullException

source 是參考 null 。

ArgumentException

source 包含一個或多個重複鍵。

備註

若 comparer ， null則預設的等號比較器 Default 用於比較金鑰。

適用於

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

來源:: ToCollection.cs

來源:: ToCollection.cs

來源:: ToCollection.cs

來源:: ToCollection.cs

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

來自元素 source的鍵型。

TValue

來自元素 source的值類型。

參數

source: IEnumerable<ValueTuple<TKey,TValue>>

列舉用來建立字典。

comparer: IEqualityComparer<TKey>

一個等式比較器來比較金鑰。

傳回

Dictionary<TKey,TValue>

一個包含鍵與值的 source字典。

例外狀況

ArgumentNullException

source 是參考 null 。

ArgumentException

source 包含一個或多個重複鍵。

備註

若 comparer ， null則預設的等號比較器 Default 用於比較金鑰。

適用於

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

來源:: ToCollection.cs

來源:: ToCollection.cs

來源:: ToCollection.cs

來源:: ToCollection.cs

來源:: ToCollection.cs

根據指定的索引鍵選取器函式、比較子和元素選取器函式，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

元素 source的類型。

TKey

由返回 keySelector的金鑰類型。

TElement

由返回 elementSelector的值類型。

參數

source: IEnumerable<TSource>

一個 IEnumerable<T> 創造一個 Dictionary<TKey,TValue> 。

keySelector: Func<TSource,TKey>

一個用來從每個元素中提取鍵值的函式。

elementSelector: Func<TSource,TElement>

一個轉換函數，從每個元素產生結果元素值。

comparer: IEqualityComparer<TKey>

還有 IEqualityComparer<T> 比較鑰匙。

傳回

Dictionary<TKey,TElement>

Dictionary<TKey,TValue> A 包含從輸入序列中選擇的值TElement。

例外狀況

ArgumentNullException

source或keySelectorelementSelector是 null。

-或-

keySelector 產生一個鍵，為 null。

ArgumentException

keySelector 產生兩個元素的重複鍵。

備註

若 comparer ， null則預設的等號比較器 Default 用於比較金鑰。

適用於

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

來源:: ToCollection.cs

來源:: ToCollection.cs

來源:: ToCollection.cs

來源:: ToCollection.cs

來源:: ToCollection.cs

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

元素 source的類型。

TKey

由返回 keySelector的金鑰類型。

TElement

由返回 elementSelector的值類型。

參數

source: IEnumerable<TSource>

一個 IEnumerable<T> 創造一個 Dictionary<TKey,TValue> 。

keySelector: Func<TSource,TKey>

一個用來從每個元素中提取鍵值的函式。

elementSelector: Func<TSource,TElement>

一個轉換函數，從每個元素產生結果元素值。

傳回

Dictionary<TKey,TElement>

Dictionary<TKey,TValue> A 包含從輸入序列中選擇的值TElement。

例外狀況

ArgumentNullException

source或keySelectorelementSelector是 null。

-或-

keySelector 產生一個鍵，為 null。

ArgumentException

keySelector 產生兩個元素的重複鍵。

備註

此 ToDictionary<TSource,TKey,TElement>(IEnumerable<TSource>, Func<TSource,TKey>, Func<TSource,TElement>) 方法使用預設的等號比較器 Default 來比較鍵。

適用於

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

來源:: ToCollection.cs

來源:: ToCollection.cs

來源:: ToCollection.cs

來源:: ToCollection.cs

來源:: ToCollection.cs

根據指定的索引鍵選取器函式，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

元素 source的類型。

TKey

由返回 keySelector的金鑰類型。

參數

source: IEnumerable<TSource>

一個 IEnumerable<T> 創造一個 Dictionary<TKey,TValue> 。

keySelector: Func<TSource,TKey>

一個用來從每個元素中提取鍵值的函式。

傳回

Dictionary<TKey,TSource>

包含鍵與值的 A Dictionary<TKey,TValue> 。每個群組內的值順序與中 source相同。

例外狀況

ArgumentNullException

source 或 keySelector 為 null。

-或-

keySelector 產生一個鍵，為 null。

ArgumentException

keySelector 產生兩個元素的重複鍵。

範例

以下程式碼範例示範如何利用ToDictionary<TSource,TKey>(IEnumerable<TSource>, Func<TSource,TKey>)鍵選擇器來建立。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

此 ToDictionary<TSource,TKey>(IEnumerable<TSource>, Func<TSource,TKey>) 方法使用預設的等號比較器 Default 來比較鍵。

適用於

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

來源:: ToCollection.cs

來源:: ToCollection.cs

來源:: ToCollection.cs

來源:: ToCollection.cs

來源:: ToCollection.cs

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)