Enumerable.ToDictionary Enumerable.ToDictionary Enumerable.ToDictionary Enumerable.ToDictionary Method

Definizione

Crea un oggetto Dictionary<TKey,TValue> da un oggetto IEnumerable<T>.Creates a Dictionary<TKey,TValue> from an IEnumerable<T>.

Overload

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

Crea un oggetto Dictionary<TKey,TValue> da un oggetto IEnumerable<T> secondo le funzioni specificate del selettore principale e del selettore di elementi.Creates a Dictionary<TKey,TValue> from an IEnumerable<T> according to specified key selector and element selector functions.

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

Crea un oggetto Dictionary<TKey,TValue> da un oggetto IEnumerable<T> secondo una funzione specificata del selettore principale, un operatore di confronto principale e una funzione del selettore di elementi.Creates a Dictionary<TKey,TValue> from an IEnumerable<T> according to a specified key selector function, a comparer, and an element selector function.

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

Crea un oggetto Dictionary<TKey,TValue> da un oggetto IEnumerable<T> secondo una funzione del selettore principale specificata.Creates a Dictionary<TKey,TValue> from an IEnumerable<T> according to a specified key selector function.

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

Crea un oggetto Dictionary<TKey,TValue> da un oggetto IEnumerable<T> secondo una funzione del selettore principale specificata e un operatore di confronto principale.Creates a Dictionary<TKey,TValue> from an IEnumerable<T> according to a specified key selector function and key comparer.

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

Crea un oggetto Dictionary<TKey,TValue> da un oggetto IEnumerable<T> secondo le funzioni specificate del selettore principale e del selettore di elementi.Creates a Dictionary<TKey,TValue> from an IEnumerable<T> according to specified key selector and element selector functions.

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)

Parametri di tipo

TSource

Tipo degli elementi di source.The type of the elements of source.

TKey

Tipo della chiave restituita dall'oggetto keySelector.The type of the key returned by keySelector.

TElement

Tipo del valore restituito dall'oggetto elementSelector.The type of the value returned by elementSelector.

Parametri

source
IEnumerable<TSource>

Oggetto IEnumerable<T> da cui creare un oggetto Dictionary<TKey,TValue>.An IEnumerable<T> to create a Dictionary<TKey,TValue> from.

keySelector
Func<TSource,TKey>

Funzione per estrarre una chiave da ogni elemento.A function to extract a key from each element.

elementSelector
Func<TSource,TElement>

Funzione di trasformazione per produrre un valore dell'elemento di risultato da ogni elemento.A transform function to produce a result element value from each element.

Restituisce

Dictionary<TKey,TElement>

Oggetto Dictionary<TKey,TValue> che contiene valori di tipo TElement selezionati dalla sequenza di input.A Dictionary<TKey,TValue> that contains values of type TElement selected from the input sequence.

Eccezioni

Il parametro source, il parametro keySelector o il parametro elementSelector è null.source or keySelector or elementSelector is null.

In alternativa-or- keySelector genera una chiave che è null.keySelector produces a key that is null.

keySelector genera chiavi duplicate per due elementi.keySelector produces duplicate keys for two elements.

Commenti

Il ToDictionary<TSource,TKey,TElement>(IEnumerable<TSource>, Func<TSource,TKey>, Func<TSource,TElement>) metodo Usa l'operatore di uguaglianza predefinito Default per confrontare le chiavi.The ToDictionary<TSource,TKey,TElement>(IEnumerable<TSource>, Func<TSource,TKey>, Func<TSource,TElement>) method uses the default equality comparer Default to compare keys.

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

Crea un oggetto Dictionary<TKey,TValue> da un oggetto IEnumerable<T> secondo una funzione specificata del selettore principale, un operatore di confronto principale e una funzione del selettore di elementi.Creates a Dictionary<TKey,TValue> from an IEnumerable<T> according to a specified key selector function, a comparer, and an element selector function.

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);
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)

Parametri di tipo

TSource

Tipo degli elementi di source.The type of the elements of source.

TKey

Tipo della chiave restituita dall'oggetto keySelector.The type of the key returned by keySelector.

TElement

Tipo del valore restituito dall'oggetto elementSelector.The type of the value returned by elementSelector.

Parametri

source
IEnumerable<TSource>

Oggetto IEnumerable<T> da cui creare un oggetto Dictionary<TKey,TValue>.An IEnumerable<T> to create a Dictionary<TKey,TValue> from.

keySelector
Func<TSource,TKey>

Funzione per estrarre una chiave da ogni elemento.A function to extract a key from each element.

elementSelector
Func<TSource,TElement>

Funzione di trasformazione per produrre un valore dell'elemento di risultato da ogni elemento.A transform function to produce a result element value from each element.

comparer
IEqualityComparer<TKey>

Oggetto IEqualityComparer<T> per confrontare le chiavi.An IEqualityComparer<T> to compare keys.

Restituisce

Dictionary<TKey,TElement>

Oggetto Dictionary<TKey,TValue> che contiene valori di tipo TElement selezionati dalla sequenza di input.A Dictionary<TKey,TValue> that contains values of type TElement selected from the input sequence.

Eccezioni

Il parametro source, il parametro keySelector o il parametro elementSelector è null.source or keySelector or elementSelector is null.

In alternativa-or- keySelector genera una chiave che è null.keySelector produces a key that is null.

keySelector genera chiavi duplicate per due elementi.keySelector produces duplicate keys for two elements.

Commenti

Se comparer viene null, l'operatore di uguaglianza predefinito Default viene usata per confrontare le chiavi.If comparer is null, the default equality comparer Default is used to compare keys.

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

Crea un oggetto Dictionary<TKey,TValue> da un oggetto IEnumerable<T> secondo una funzione del selettore principale specificata.Creates a Dictionary<TKey,TValue> from an IEnumerable<T> according to a specified key selector function.

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)

Parametri di tipo

TSource

Tipo degli elementi di source.The type of the elements of source.

TKey

Tipo della chiave restituita dall'oggetto keySelector.The type of the key returned by keySelector.

Parametri

source
IEnumerable<TSource>

Oggetto IEnumerable<T> da cui creare un oggetto Dictionary<TKey,TValue>.An IEnumerable<T> to create a Dictionary<TKey,TValue> from.

keySelector
Func<TSource,TKey>

Funzione per estrarre una chiave da ogni elemento.A function to extract a key from each element.

Restituisce

Dictionary<TKey,TSource>

Oggetto Dictionary<TKey,TValue> che contiene chiavi e valori.A Dictionary<TKey,TValue> that contains keys and values.

Eccezioni

source o keySelector è null.source or keySelector is null.

In alternativa-or- keySelector genera una chiave che è null.keySelector produces a key that is null.

keySelector genera chiavi duplicate per due elementi.keySelector produces duplicate keys for two elements.

Esempi

Esempio di codice seguente viene illustrato come utilizzare ToDictionary<TSource,TKey>(IEnumerable<TSource>, Func<TSource,TKey>) per creare un Dictionary<TKey,TValue> mediante un selettore di chiave.The following code example demonstrates how to use ToDictionary<TSource,TKey>(IEnumerable<TSource>, Func<TSource,TKey>) to create a Dictionary<TKey,TValue> by using a key selector.

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
    MsgBox(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

Commenti

Il ToDictionary<TSource,TKey>(IEnumerable<TSource>, Func<TSource,TKey>) metodo Usa l'operatore di uguaglianza predefinito Default per confrontare le chiavi.The ToDictionary<TSource,TKey>(IEnumerable<TSource>, Func<TSource,TKey>) method uses the default equality comparer Default to compare keys.

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

Crea un oggetto Dictionary<TKey,TValue> da un oggetto IEnumerable<T> secondo una funzione del selettore principale specificata e un operatore di confronto principale.Creates a Dictionary<TKey,TValue> from an IEnumerable<T> according to a specified key selector function and key comparer.

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);
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)

Parametri di tipo

TSource

Tipo degli elementi di source.The type of the elements of source.

TKey

Tipo delle chiavi restituite dall'oggetto keySelector.The type of the keys returned by keySelector.

Parametri

source
IEnumerable<TSource>

Oggetto IEnumerable<T> da cui creare un oggetto Dictionary<TKey,TValue>.An IEnumerable<T> to create a Dictionary<TKey,TValue> from.

keySelector
Func<TSource,TKey>

Funzione per estrarre una chiave da ogni elemento.A function to extract a key from each element.

comparer
IEqualityComparer<TKey>

Oggetto IEqualityComparer<T> per confrontare le chiavi.An IEqualityComparer<T> to compare keys.

Restituisce

Dictionary<TKey,TSource>

Oggetto Dictionary<TKey,TValue> che contiene chiavi e valori.A Dictionary<TKey,TValue> that contains keys and values.

Eccezioni

source o keySelector è null.source or keySelector is null.

In alternativa-or- keySelector genera una chiave che è null.keySelector produces a key that is null.

keySelector genera chiavi duplicate per due elementi.keySelector produces duplicate keys for two elements.

Commenti

Se comparer viene null, l'operatore di uguaglianza predefinito Default viene usata per confrontare le chiavi.If comparer is null, the default equality comparer Default is used to compare keys.

Si applica a