# Enumerable.SequenceEqualEnumerable.SequenceEqualEnumerable.SequenceEqualEnumerable.SequenceEqual Method

## 多載

 SequenceEqual(IEnumerable, IEnumerable) SequenceEqual(IEnumerable, IEnumerable) SequenceEqual(IEnumerable, IEnumerable) SequenceEqual(IEnumerable, IEnumerable) 判斷兩個序列是否相等，藉由其類型使用預設相等比較子來比較項目。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) 判斷兩個序列是否相等，藉由使用指定的比較其項目IEqualityComparer。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>)

``````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``````

TSource

#### 參數

first
IEnumerable<TSource>

IEnumerable<T>比較`second`An IEnumerable<T> to compare to `second`.

second
IEnumerable<TSource>

IEnumerable<T>来比較的第一個序列。An IEnumerable<T> to compare to the first sequence.

#### 傳回

`true` 如果兩個來源序列的長度相等，而且其對應的項目相等的預設相等比較子，其類型; 根據否則， `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`.

#### 例外狀況

`first``second``null``first` or `second` is `null`.

### 範例

``````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.
``````

``````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.
``````

``````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
``````

``````
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
``````

### 備註

`SequenceEqual<TSource>(IEnumerable<TSource>, IEnumerable<TSource>)`方法列舉兩個來源序列，以平行方式，並使用預設相等比較子來比較對應項目`TSource`DefaultThe `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.

## 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>)

``````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``````

TSource

#### 參數

first
IEnumerable<TSource>

IEnumerable<T>比較`second`An IEnumerable<T> to compare to `second`.

second
IEnumerable<TSource>

IEnumerable<T>来比較的第一個序列。An IEnumerable<T> to compare to the first sequence.

comparer
IEqualityComparer<TSource>

IEqualityComparer<T>用來比較項目。An IEqualityComparer<T> to use to compare elements.

#### 傳回

`true` 如果兩個來源序列的長度相等，而且其對應的項目進行比較時相等，根據`comparer`; 否則`false``true` if the two source sequences are of equal length and their corresponding elements compare equal according to `comparer`; otherwise, `false`.

#### 例外狀況

`first``second``null``first` or `second` is `null`.

### 範例

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
``````

``````
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
``````

### 備註

SequenceEqual<TSource>(IEnumerable<TSource>, IEnumerable<TSource>, IEqualityComparer<TSource>)方法會列舉兩個來源序列，以平行方式，並比較使用指定的對應項目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>. 如果`comparer``null`，預設的相等比較子， Default，用來比較項目。If `comparer` is `null`, the default equality comparer, Default, is used to compare elements.