# Enumerable.SequenceEqualEnumerable.SequenceEqualEnumerable.SequenceEqualEnumerable.SequenceEqual Method

## Definizione

Determina se due sequenze sono uguali secondo un operatore di confronto di uguaglianza.Determines whether two sequences are equal according to an equality comparer.

 SequenceEqual(IEnumerable, IEnumerable) SequenceEqual(IEnumerable, IEnumerable) SequenceEqual(IEnumerable, IEnumerable) SequenceEqual(IEnumerable, IEnumerable) Determina se due sequenze sono uguali confrontando gli elementi tramite l’uso dell'operatore di confronto uguaglianze predefinito per il loro tipo.Determines whether two sequences are equal by comparing the elements by using the default equality comparer for their type. SequenceEqual(IEnumerable, IEnumerable, IEqualityComparer) SequenceEqual(IEnumerable, IEnumerable, IEqualityComparer) SequenceEqual(IEnumerable, IEnumerable, IEqualityComparer) SequenceEqual(IEnumerable, IEnumerable, IEqualityComparer) Determina se due sequenze sono uguali confrontando i loro elementi mediante l’uso di un oggetto IEqualityComparer specificato.Determines whether two sequences are equal by comparing their elements by using a specified IEqualityComparer.

## SequenceEqual<TSource>(IEnumerable<TSource>, IEnumerable<TSource>)SequenceEqual<TSource>(IEnumerable<TSource>, IEnumerable<TSource>)SequenceEqual<TSource>(IEnumerable<TSource>, IEnumerable<TSource>)SequenceEqual<TSource>(IEnumerable<TSource>, IEnumerable<TSource>)

Determina se due sequenze sono uguali confrontando gli elementi tramite l’uso dell'operatore di confronto uguaglianze predefinito per il loro tipo.Determines whether two sequences are equal by comparing the elements by using the default equality comparer for their type.

``````public:
generic <typename TSource>
[System::Runtime::CompilerServices::Extension]
static bool SequenceEqual(System::Collections::Generic::IEnumerable<TSource> ^ first, System::Collections::Generic::IEnumerable<TSource> ^ second);``````
``public static bool SequenceEqual<TSource> (this System.Collections.Generic.IEnumerable<TSource> first, System.Collections.Generic.IEnumerable<TSource> second);``
``static member SequenceEqual : seq<'Source> * seq<'Source> -> bool``
``````<Extension()>
Public Function SequenceEqual(Of TSource) (first As IEnumerable(Of TSource), second As IEnumerable(Of TSource)) As Boolean``````

#### Parametri di tipo

TSource

Tipo degli elementi delle sequenze di input.The type of the elements of the input sequences.

#### Parametri

first
IEnumerable<TSource>

Oggetto IEnumerable<T> da confrontare a `second`.An IEnumerable<T> to compare to `second`.

second
IEnumerable<TSource>

Oggetto IEnumerable<T> da confrontare alla prima sequenza.An IEnumerable<T> to compare to the first sequence.

#### Restituisce

`true` se le due sequenze di origine sono di lunghezza uguale e gli elementi corrispondenti risultano uguali secondo l’operatore di confronto uguaglianze per il loro tipo; in caso contrario, `false`.`true` if the two source sequences are of equal length and their corresponding elements are equal according to the default equality comparer for their type; otherwise, `false`.

#### Eccezioni

`first` o `second` è `null`.`first` or `second` is `null`.

### Esempi

Gli esempi di codice seguenti illustrano come usare `SequenceEqual<TSource>(IEnumerable<TSource>, IEnumerable<TSource>)` per determinare se due sequenze sono uguali.The following code examples demonstrate how to use `SequenceEqual<TSource>(IEnumerable<TSource>, IEnumerable<TSource>)` to determine whether two sequences are equal. Nei primi due esempi, il metodo determina se le sequenze confrontate contengono riferimenti agli oggetti stessi.In the first two examples, the method determines whether the compared sequences contain references to the same objects. Negli esempi terzi e quarto, il metodo confronta i dati effettivi degli oggetti all'interno delle sequenze.In the third and fourth examples, the method compares the actual data of the objects within the sequences.

In questo esempio le sequenze sono uguali.In this example the sequences are equal.

``````class Pet
{
public string Name { get; set; }
public int Age { get; set; }
}

public static void SequenceEqualEx1()
{
Pet pet1 = new Pet { Name = "Turbo", Age = 2 };
Pet pet2 = new Pet { Name = "Peanut", Age = 8 };

// Create two lists of pets.
List<Pet> pets1 = new List<Pet> { pet1, pet2 };
List<Pet> pets2 = new List<Pet> { pet1, pet2 };

bool equal = pets1.SequenceEqual(pets2);

Console.WriteLine(
"The lists {0} equal.",
equal ? "are" : "are not");
}

/*
This code produces the following output:

The lists are equal.
*/
``````
``````Class Pet
Public Name As String
Public Age As Integer
End Class

Sub SequenceEqualEx1()
' Create two Pet objects.
Dim pet1 As New Pet With {.Name = "Turbo", .Age = 2}
Dim pet2 As New Pet With {.Name = "Peanut", .Age = 8}

' Create two lists of pets.
Dim pets1 As New List(Of Pet)(New Pet() {pet1, pet2})
Dim pets2 As New List(Of Pet)(New Pet() {pet1, pet2})

'Determine if the two lists are equal.
Dim equal As Boolean = pets1.SequenceEqual(pets2)

' Display the output.
Dim text As String = IIf(equal, "are", "are not")
MsgBox("The lists " & text & " equal.")

End Sub

' This code produces the following output:
'
' The lists are equal.
``````

Esempio di codice seguente consente di confrontare due sequenze che non sono uguali.The following code example compares two sequences that are not equal. Si noti che le sequenze contengono dati identici, ma poiché gli oggetti in essi contenuti hanno diversi riferimenti, le sequenze non sono considerate uguali.Note that the sequences contain identical data, but because the objects that they contain have different references, the sequences are not considered equal.

``````class Pet
{
public string Name { get; set; }
public int Age { get; set; }
}

public static void SequenceEqualEx2()
{
Pet pet1 = new Pet() { Name = "Turbo", Age = 2 };
Pet pet2 = new Pet() { Name = "Peanut", Age = 8 };

// Create two lists of pets.
List<Pet> pets1 = new List<Pet> { pet1, pet2 };
List<Pet> pets2 =
new List<Pet> { new Pet { Name = "Turbo", Age = 2 },
new Pet { Name = "Peanut", Age = 8 } };

bool equal = pets1.SequenceEqual(pets2);

Console.WriteLine("The lists {0} equal.", equal ? "are" : "are not");
}

/*
This code produces the following output:

The lists are not equal.
*/
``````
``````' Create two Pet objects.
Dim pet1 As New Pet With {.Name = "Turbo", .Age = 2}
Dim pet2 As New Pet With {.Name = "Peanut", .Age = 8}

' Create two lists of pets.
Dim pets1 As New List(Of Pet)()

Dim pets2 As New List(Of Pet)()
pets2.Add(New Pet With {.Name = "Turbo", .Age = 2})
pets2.Add(New Pet With {.Name = "Peanut", .Age = 8})

' Determine if the two lists are equal.
Dim equal As Boolean = pets1.SequenceEqual(pets2)

' Display the output.
Dim text As String = IIf(equal, "are", "are not")
MsgBox("The lists " & text & " equal.")

' This code produces the following output:
'
' The lists are not equal.
``````

Se si desidera confrontare i dati degli oggetti nelle sequenze anziché confrontare solo i riferimenti relativi effettivi, è necessario implementare il IEqualityComparer<T> generica interfaccia nella classe.If you want to compare the actual data of the objects in the sequences instead of just comparing their references, you have to implement the IEqualityComparer<T> generic interface in your class. Esempio di codice seguente viene illustrato come implementare questa interfaccia in una classe helper e fornire GetHashCode e Equals metodi.The following code example shows how to implement this interface in a helper class and provide GetHashCode and Equals methods.

``````public class ProductA: IEquatable<ProductA>
{
public string Name { get; set; }
public int Code { get; set; }

public bool Equals(ProductA other)
{
if (other is null)
return false;

return this.Name == other.Name && this.Code == other.Code;
}

public override bool Equals(object obj) => Equals(obj as ProductA);
public override int GetHashCode() => (Name, Code).GetHashCode();
}
``````
``````Public Class ProductA
Inherits IEquatable(Of ProductA)

Public Property Name As String
Public Property Code As Integer

Public Function Equals(ByVal other As ProductA) As Boolean
If other Is Nothing Then Return False
Return Me.Name = other.Name AndAlso Me.Code = other.Code
End Function

Public Overrides Function Equals(ByVal obj As Object) As Boolean
Return Equals(TryCast(obj, ProductA))
End Function

Public Overrides Function GetHashCode() As Integer
Return (Name, Code).GetHashCode()
End Function

End Class
``````

Dopo aver implementato questa interfaccia, è possibile usare le sequenze di `ProductA` oggetti nel `SequenceEqual<TSource>(IEnumerable<TSource>, IEnumerable<TSource>)` metodo, come illustrato nell'esempio seguente:After you implement this interface, you can use sequences of `ProductA` objects in the `SequenceEqual<TSource>(IEnumerable<TSource>, IEnumerable<TSource>)` method, as shown in the following example:

``````
ProductA[] storeA = { new ProductA { Name = "apple", Code = 9 },
new ProductA { Name = "orange", Code = 4 } };

ProductA[] storeB = { new ProductA { Name = "apple", Code = 9 },
new ProductA { Name = "orange", Code = 4 } };

bool equalAB = storeA.SequenceEqual(storeB);

Console.WriteLine("Equal? " + equalAB);

/*
This code produces the following output:

Equal? True
*/
``````
``````Dim storeA() As Product =
{New Product With {.Name = "apple", .Code = 9},
New Product With {.Name = "orange", .Code = 4}}

Dim storeB() As Product =
{New Product With {.Name = "apple", .Code = 9},
New Product With {.Name = "orange", .Code = 4}}

Dim equalAB = storeA.SequenceEqual(storeB)

Console.WriteLine("Equal? " & equalAB)

' This code produces the following output:

' Equal? True
``````

### Commenti

Il `SequenceEqual<TSource>(IEnumerable<TSource>, IEnumerable<TSource>)` metodo enumera le due sequenze di origine in parallelo e confronta gli elementi corrispondenti usando l'operatore di confronto uguaglianze predefinito per `TSource`, Default.The `SequenceEqual<TSource>(IEnumerable<TSource>, IEnumerable<TSource>)` method enumerates the two source sequences in parallel and compares corresponding elements by using the default equality comparer for `TSource`, Default.

Operatore di uguaglianza predefinito, Default, viene usata per confrontare i valori dei tipi.The default equality comparer, Default, is used to compare values of the types. Per confrontare un tipo di dati personalizzato, è necessario eseguire l'override di Equals e il GetHashCode metodi e, facoltativamente, implementare il IEquatable<T> interfaccia generica di tipo personalizzato.To compare a custom data type, you need to override the Equals and the GetHashCode methods, and optionally implement the IEquatable<T> generic interface in the custom type. Per altre informazioni, vedere la proprietà Default.For more information, see the Default property.

## SequenceEqual<TSource>(IEnumerable<TSource>, IEnumerable<TSource>, IEqualityComparer<TSource>)SequenceEqual<TSource>(IEnumerable<TSource>, IEnumerable<TSource>, IEqualityComparer<TSource>)SequenceEqual<TSource>(IEnumerable<TSource>, IEnumerable<TSource>, IEqualityComparer<TSource>)SequenceEqual<TSource>(IEnumerable<TSource>, IEnumerable<TSource>, IEqualityComparer<TSource>)

Determina se due sequenze sono uguali confrontando i loro elementi mediante l’uso di un oggetto IEqualityComparer<T> specificato.Determines whether two sequences are equal by comparing their elements by using a specified IEqualityComparer<T>.

``````public:
generic <typename TSource>
[System::Runtime::CompilerServices::Extension]
static bool SequenceEqual(System::Collections::Generic::IEnumerable<TSource> ^ first, System::Collections::Generic::IEnumerable<TSource> ^ second, System::Collections::Generic::IEqualityComparer<TSource> ^ comparer);``````
``public static bool SequenceEqual<TSource> (this System.Collections.Generic.IEnumerable<TSource> first, System.Collections.Generic.IEnumerable<TSource> second, System.Collections.Generic.IEqualityComparer<TSource> comparer);``
``static member SequenceEqual : seq<'Source> * seq<'Source> * System.Collections.Generic.IEqualityComparer<'Source> -> bool``
``````<Extension()>
Public Function SequenceEqual(Of TSource) (first As IEnumerable(Of TSource), second As IEnumerable(Of TSource), comparer As IEqualityComparer(Of TSource)) As Boolean``````

#### Parametri di tipo

TSource

Tipo degli elementi delle sequenze di input.The type of the elements of the input sequences.

#### Parametri

first
IEnumerable<TSource>

Oggetto IEnumerable<T> da confrontare a `second`.An IEnumerable<T> to compare to `second`.

second
IEnumerable<TSource>

Oggetto IEnumerable<T> da confrontare alla prima sequenza.An IEnumerable<T> to compare to the first sequence.

comparer
IEqualityComparer<TSource>

Oggetto IEqualityComparer<T> da usare per confrontare gli elementi.An IEqualityComparer<T> to use to compare elements.

#### Restituisce

`true` se le due sequenze di origine sono di lunghezza uguale e gli elementi corrispondenti risultano uguali secondo `comparer`; in caso contrario, `false`.`true` if the two source sequences are of equal length and their corresponding elements compare equal according to `comparer`; otherwise, `false`.

#### Eccezioni

`first` o `second` è `null`.`first` or `second` is `null`.

### Esempi

Nell'esempio seguente viene illustrato come implementare un operatore di confronto di uguaglianze che può essere usato nel SequenceEqual<TSource>(IEnumerable<TSource>, IEnumerable<TSource>, IEqualityComparer<TSource>) (metodo).The following example shows how to implement an equality comparer that can be used in the SequenceEqual<TSource>(IEnumerable<TSource>, IEnumerable<TSource>, IEqualityComparer<TSource>) method.

``````public class Product
{
public string Name { get; set; }
public int Code { get; set; }
}

// Custom comparer for the Product class
class ProductComparer : IEqualityComparer<Product>
{
// Products are equal if their names and product numbers are equal.
public bool Equals(Product x, Product y)
{

//Check whether the compared objects reference the same data.
if (Object.ReferenceEquals(x, y)) return true;

//Check whether any of the compared objects is null.
if (Object.ReferenceEquals(x, null) || Object.ReferenceEquals(y, null))
return false;

//Check whether the products' properties are equal.
return x.Code == y.Code && x.Name == y.Name;
}

// If Equals() returns true for a pair of objects
// then GetHashCode() must return the same value for these objects.

public int GetHashCode(Product product)
{
//Check whether the object is null
if (Object.ReferenceEquals(product, null)) return 0;

//Get hash code for the Name field if it is not null.
int hashProductName = product.Name == null ? 0 : product.Name.GetHashCode();

//Get hash code for the Code field.
int hashProductCode = product.Code.GetHashCode();

//Calculate the hash code for the product.
return hashProductName ^ hashProductCode;
}

}
``````
``````Public Class Product
Public Property Name As String
Public Property Code As Integer
End Class

' Custom comparer for the Product class
Public Class ProductComparer
Implements IEqualityComparer(Of Product)

Public Function Equals1(
ByVal x As Product,
ByVal y As Product
) As Boolean Implements IEqualityComparer(Of Product).Equals

' Check whether the compared objects reference the same data.
If x Is y Then Return True

'Check whether any of the compared objects is null.
If x Is Nothing OrElse y Is Nothing Then Return False

' Check whether the products' properties are equal.
Return (x.Code = y.Code) AndAlso (x.Name = y.Name)
End Function

Public Function GetHashCode1(
ByVal product As Product
) As Integer Implements IEqualityComparer(Of Product).GetHashCode

' Check whether the object is null.
If product Is Nothing Then Return 0

' Get hash code for the Name field if it is not null.
Dim hashProductName =
If(product.Name Is Nothing, 0, product.Name.GetHashCode())

' Get hash code for the Code field.
Dim hashProductCode = product.Code.GetHashCode()

' Calculate the hash code for the product.
Return hashProductName Xor hashProductCode
End Function
End Class
``````

Dopo aver implementato questo operatore di confronto, è possibile usare le sequenze di `Product` oggetti nel SequenceEqual<TSource>(IEnumerable<TSource>, IEnumerable<TSource>, IEqualityComparer<TSource>) metodo, come illustrato nell'esempio seguente:After you implement this comparer, you can use sequences of `Product` objects in the SequenceEqual<TSource>(IEnumerable<TSource>, IEnumerable<TSource>, IEqualityComparer<TSource>) method, as shown in the following example:

``````
Product[] storeA = { new Product { Name = "apple", Code = 9 },
new Product { Name = "orange", Code = 4 } };

Product[] storeB = { new Product { Name = "apple", Code = 9 },
new Product { Name = "orange", Code = 4 } };

bool equalAB = storeA.SequenceEqual(storeB, new ProductComparer());

Console.WriteLine("Equal? " + equalAB);

/*
This code produces the following output:

Equal? True
*/

``````
``````
Dim storeA() As Product =
{New Product With {.Name = "apple", .Code = 9},
New Product With {.Name = "orange", .Code = 4}}

Dim storeB() As Product =
{New Product With {.Name = "apple", .Code = 9},
New Product With {.Name = "orange", .Code = 4}}

Dim equalAB = storeA.SequenceEqual(storeB, New ProductComparer())

Console.WriteLine("Equal? " & equalAB)

' This code produces the following output:

' Equal? True
``````

### Commenti

Il SequenceEqual<TSource>(IEnumerable<TSource>, IEnumerable<TSource>, IEqualityComparer<TSource>) metodo enumera le due sequenze di origine in parallelo e consente di confrontare gli elementi corrispondenti in utilizzando l'oggetto specificato IEqualityComparer<T>.The SequenceEqual<TSource>(IEnumerable<TSource>, IEnumerable<TSource>, IEqualityComparer<TSource>) method enumerates the two source sequences in parallel and compares corresponding elements by using the specified IEqualityComparer<T>. Se `comparer` viene `null`, l'operatore di confronto uguaglianze predefinito, Default, viene utilizzato per confrontare gli elementi.If `comparer` is `null`, the default equality comparer, Default, is used to compare elements.