Enumerable.ToArray<TSource>(IEnumerable<TSource>) 方法
定义
重要
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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
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。
