List<T>.ConvertAll<TOutput>(Converter<T,TOutput>) 方法

public:
generic <typename TOutput>
 System::Collections::Generic::List<TOutput> ^ ConvertAll(Converter<T, TOutput> ^ converter);

public System.Collections.Generic.List<TOutput> ConvertAll<TOutput> (Converter<T,TOutput> converter);

member this.ConvertAll : Converter<'T, 'Output> -> System.Collections.Generic.List<'Output>

Public Function ConvertAll(Of TOutput) (converter As Converter(Of T, TOutput)) As List(Of TOutput)

类型参数

参数

返回

List<TOutput>

目标类型的 List<T>，包含当前 List<T> 中转换后的元素。A List<T> of the target type containing the converted elements from the current List<T>.

例外

示例

下面的示例定义了一个名为 PointFToPoint 的方法，该方法将 PointF 结构转换为 Point 结构。The following example defines a method named PointFToPoint that converts a PointF structure to a Point structure. 然后，该示例创建了一个 List<T> PointF 结构， Converter\<PointF, Point> Converter(Of PointF, Point) 在 Visual Basic) 中创建委托 (来表示 PointFToPoint 方法，并将委托传递给 ConvertAll 方法。The example then creates a List<T> of PointF structures, creates a Converter\<PointF, Point> delegate (Converter(Of PointF, Point) in Visual Basic) to represent the PointFToPoint method, and passes the delegate to the ConvertAll method. ConvertAll方法将输入列表的每个元素传递给 PointFToPoint 方法，并将转换后的元素放入新的 Point 结构列表。The ConvertAll method passes each element of the input list to the PointFToPoint method and puts the converted elements into a new list of Point structures. 将显示这两个列表。Both lists are displayed.

#using <System.Drawing.dll>

using namespace System;
using namespace System::Drawing;
using namespace System::Collections::Generic;

Point PointFToPoint(PointF pf)
{
    return Point((int) pf.X, (int) pf.Y);
};

void main()
{
    List<PointF>^ lpf = gcnew List<PointF>();

    lpf->Add(PointF(27.8F, 32.62F));
    lpf->Add(PointF(99.3F, 147.273F));
    lpf->Add(PointF(7.5F, 1412.2F));

    Console::WriteLine();
    for each(PointF p in lpf)
    {
        Console::WriteLine(p);
    }

    List<Point>^ lp = 
        lpf->ConvertAll<Point>(
            gcnew Converter<PointF, Point>(PointFToPoint)
        );

    Console::WriteLine();
    for each(Point p in lp)
    {
        Console::WriteLine(p);
    }
}

/* This code example produces the following output:

{X=27.8, Y=32.62}
{X=99.3, Y=147.273}
{X=7.5, Y=1412.2}

{X=27,Y=32}
{X=99,Y=147}
{X=7,Y=1412}
 */

using System;
using System.Drawing;
using System.Collections.Generic;

public class Example
{
    public static void Main()
    {
        List<PointF> lpf = new List<PointF>();

        lpf.Add(new PointF(27.8F, 32.62F));
        lpf.Add(new PointF(99.3F, 147.273F));
        lpf.Add(new PointF(7.5F, 1412.2F));

        Console.WriteLine();
        foreach( PointF p in lpf )
        {
            Console.WriteLine(p);
        }

        List<Point> lp = lpf.ConvertAll(
            new Converter<PointF, Point>(PointFToPoint));

        Console.WriteLine();
        foreach( Point p in lp )
        {
            Console.WriteLine(p);
        }
    }

    public static Point PointFToPoint(PointF pf)
    {
        return new Point(((int) pf.X), ((int) pf.Y));
    }
}

/* This code example produces the following output:

{X=27.8, Y=32.62}
{X=99.3, Y=147.273}
{X=7.5, Y=1412.2}

{X=27,Y=32}
{X=99,Y=147}
{X=7,Y=1412}
 */

Imports System.Drawing
Imports System.Collections.Generic

Public Class Example

    Public Shared Sub Main()

        Dim lpf As New List(Of PointF)

        lpf.Add(New PointF(27.8, 32.62))
        lpf.Add(New PointF(99.3, 147.273))
        lpf.Add(New PointF(7.5, 1412.2))

        Console.WriteLine()
        For Each p As PointF In lpf
            Console.WriteLine(p)
        Next

        Dim lp As List(Of Point) = lpf.ConvertAll( _
            New Converter(Of PointF, Point)(AddressOf PointFToPoint))

        Console.WriteLine()
        For Each p As Point In lp
            Console.WriteLine(p)
        Next

    End Sub

    Public Shared Function PointFToPoint(ByVal pf As PointF) _
        As Point

        Return New Point(CInt(pf.X), CInt(pf.Y))
    End Function
End Class

' This code example produces the following output:
'
'{X=27.8, Y=32.62}
'{X=99.3, Y=147.273}
'{X=7.5, Y=1412.2}
'
'{X=28,Y=33}
'{X=99,Y=147}
'{X=8,Y=1412}

注解

Converter<TInput,TOutput>是一个方法委托，该委托将对象转换为目标类型。The Converter<TInput,TOutput> is a delegate to a method that converts an object to the target type. 当前的元素 List<T> 分别传递到 Converter<TInput,TOutput> 委托，转换后的元素保存在新的中 List<T> 。The elements of the current List<T> are individually passed to the Converter<TInput,TOutput> delegate, and the converted elements are saved in the new List<T>.

当前 List<T> 保持不变。The current List<T> remains unchanged.

此方法是 O (n) 操作，其中 n 是 Count 。This method is an O(n) operation, where n is Count.

适用于

另请参阅

• Converter<TInput,TOutput>