Enumerable.ToArray<TSource>(IEnumerable<TSource>) 方法

定义

命名空间:

System.Linq

程序集:

System.Linq.dll

Source:

ToCollection.cs

从 IEnumerable<T> 中创建数组。

public:
generic <typename TSource>
[System::Runtime::CompilerServices::Extension]
 static cli::array <TSource> ^ ToArray(System::Collections::Generic::IEnumerable<TSource> ^ source);

public static TSource[] ToArray<TSource> (this System.Collections.Generic.IEnumerable<TSource> source);

static member ToArray : seq<'Source> -> 'Source[]

<Extension()>
Public Function ToArray(Of TSource) (source As IEnumerable(Of TSource)) As TSource()

类型参数

TSource

source 的元素类型。

参数

source

IEnumerable<TSource>

要从其创建数组的 IEnumerable<T>。

返回

TSource[]

一个包含输入序列中的元素的数组。

例外

ArgumentNullException

source 为 null。

示例

下面的代码示例演示如何使用 ToArray 强制立即查询计算并返回结果数组。

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

public static void ToArrayEx1()
{
    List<Package> packages =
        new List<Package>
            { new Package { Company = "Coho Vineyard", Weight = 25.2 },
              new Package { Company = "Lucerne Publishing", Weight = 18.7 },
              new Package { Company = "Wingtip Toys", Weight = 6.0 },
              new Package { Company = "Adventure Works", Weight = 33.8 } };

    string[] companies = packages.Select(pkg => pkg.Company).ToArray();

    foreach (string company in companies)
    {
        Console.WriteLine(company);
    }
}

/*
 This code produces the following output:

 Coho Vineyard
 Lucerne Publishing
 Wingtip Toys
 Adventure Works
*/

Structure Package
    Public Company As String
    Public Weight As Double
End Structure

Sub ToArrayEx1()
    ' Create a list of Package values.
    Dim packages As New List(Of Package)(New Package() _
     {New Package With {.Company = "Coho Vineyard", .Weight = 25.2},
      New Package With {.Company = "Lucerne Publishing", .Weight = 18.7},
      New Package With {.Company = "Wingtip Toys", .Weight = 6.0},
      New Package With {.Company = "Adventure Works", .Weight = 33.8}})

    ' Project the Company values from each item in the list
    ' and put them into an array.
    Dim companies() As String =
    packages _
    .Select(Function(pkg) pkg.Company) _
    .ToArray()

    ' Display the results.
    Dim output As New System.Text.StringBuilder
    For Each company As String In companies
        output.AppendLine(company)
    Next
    Console.WriteLine(output.ToString())
End Sub

' This code produces the following output:
'
' Coho Vineyard
' Lucerne Publishing
' Wingtip Toys
' Adventure Works

注解

方法 ToArray<TSource>(IEnumerable<TSource>) 强制立即计算查询，并返回包含查询结果的数组。 可以将此方法追加到查询中，以获取查询结果的缓存副本。

ToList 具有类似的行为， List<T> 但返回 而不是数组。