Converter<TInput,TOutput> Converter<TInput,TOutput> Converter<TInput,TOutput> Converter<TInput,TOutput> Delegate

定義

表示將物件從某個型別轉換成另一個型別的方法。Represents a method that converts an object from one type to another type.

generic <typename TInput, typename TOutput>
public delegate TOutput Converter(TInput input);
public delegate TOutput Converter<in TInput,out TOutput>(TInput input);
type Converter<'Input, 'Output> = delegate of 'Input -> 'Output
Public Delegate Function Converter(Of In TInput, Out TOutput)(input As TInput) As TOutput 

類型參數

TInput

要轉換的成員型別。The type of object that is to be converted.

TOutput

輸入物件要轉換成的型別。The type the input object is to be converted to.

參數

input

要轉換的物件。The object to convert.

傳回值

TOutput

TOutput,表示轉換的 TInputThe TOutput that represents the converted TInput.

繼承
Converter<TInput,TOutput>Converter<TInput,TOutput>Converter<TInput,TOutput>Converter<TInput,TOutput>

範例

本節包含兩個程式碼範例。This section contains two code examples. 第一個範例會Converter<TInput,TOutput> ConvertAll使用Array類別的方法來示範委派, 而第二個範例會使用List<T>泛型ConvertAll類別的方法來示範委派。The first demonstrates the Converter<TInput,TOutput> delegate with the ConvertAll method of the Array class, and the second demonstrates the delegate with the ConvertAll method of the List<T> generic class.

範例 1Example 1

下列程式碼範例會定義名為PointFToPoint的方法, PointF將結構轉換Point為結構。The following code example defines a method named PointFToPoint that converts a PointF structure to a Point structure. 然後, 此範例會建立結構PointF的陣列、 Converter<PointF, Point>建立委派 (Converter(Of PointF, Point)在 Visual Basic 中) 來代表PointFToPoint方法, 並將委派傳遞至ConvertAll方法。The example then creates an array 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. 方法會將輸入清單的每個元素傳遞PointFToPoint至方法, 並將已轉換的元素放入新Point的結構清單。 ConvertAllThe 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. 這兩個清單都會顯示。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()
{
    // Create an array of PointF objects.
    array<PointF>^ apf = {
        PointF(27.8F, 32.62F),
        PointF(99.3F, 147.273F),
        PointF(7.5F, 1412.2F) };


    // Display each element in the PointF array.
    Console::WriteLine();
    for each(PointF p in apf)
    {
        Console::WriteLine(p);
    }

    // Convert each PointF element to a Point object.
    array<Point>^ ap = 
        Array::ConvertAll(apf, 
            gcnew Converter<PointF, Point>(PointFToPoint)
        );

    // Display each element in the Point array.
    Console::WriteLine();
    for each(Point p in ap)
    {
        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()
    {
        // Create an array of PointF objects.
        PointF[] apf = {
            new PointF(27.8F, 32.62F),
            new PointF(99.3F, 147.273F),
            new PointF(7.5F, 1412.2F) };

        // Display each element in the PointF array.
        Console.WriteLine();
        foreach( PointF p in apf )
            Console.WriteLine(p);

        // Convert each PointF element to a Point object.
        Point[] ap = Array.ConvertAll(apf, 
            new Converter<PointF, Point>(PointFToPoint));

        // Display each element in the Point array.
        Console.WriteLine();
        foreach( Point p in ap )
        {
            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()
        ' Create an array of PointF objects.
        Dim apf() As PointF = { _
            New PointF(27.8, 32.62), _
            New PointF(99.3, 147.273), _
            New PointF(7.5, 1412.2)  }

        ' Display each element in the PointF array.
        Console.WriteLine()
        For Each p As PointF In apf
            Console.WriteLine(p)
        Next
        
        ' Convert each PointF element to a Point object.
        Dim ap() As Point = Array.ConvertAll(apf, _
            New Converter(Of PointF, Point)(AddressOf PointFToPoint))

        ' Display each element in the Point array.
        Console.WriteLine()
        For Each p As Point In ap
            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
' The 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}

範例 2Example 2

下列程式碼範例會定義名為PointFToPoint的方法, PointF將結構轉換Point為結構。The following code example defines a method named PointFToPoint that converts a PointF structure to a Point structure. 然後, 此範例會List<T>建立PointF結構的, Converter\<PointF, Point>建立PointFToPoint委派 (Converter(Of PointF, Point)在 Visual Basic 中) ConvertAll來代表方法, 並將委派傳遞至方法。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. 方法會將輸入清單的每個元素傳遞PointFToPoint至方法, 並將已轉換的元素放入新Point的結構清單。 ConvertAllThe 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. 這兩個清單都會顯示。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}

備註

ConvertAll這個委派是由Array類別的方法List<T>ConvertAll類別的方法所使用, 可將集合中的每個元素轉換成另一個類型。This delegate is used by the ConvertAll method of the Array class and the ConvertAll method of the List<T> class to convert each element of the collection from one type to another.

擴充方法

GetMethodInfo(Delegate) GetMethodInfo(Delegate) GetMethodInfo(Delegate) GetMethodInfo(Delegate)

取得表示特定委派所代表之方法的物件。Gets an object that represents the method represented by the specified delegate.

適用於