Converter<TInput,TOutput> Delegate
Definition
Important
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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);public delegate TOutput Converter<TInput,TOutput>(TInput input);type Converter<'Input, 'Output> = delegate of 'Input -> 'OutputPublic Delegate Function Converter(Of In TInput, Out TOutput)(input As TInput) As TOutput Public Delegate Function Converter(Of TInput, TOutput)(input As TInput) As TOutput Type Parameters
- TInput
The type of object that is to be converted.
This type parameter is contravariant. That is, you can use either the type you specified or any type that is less derived. For more information about covariance and contravariance, see Covariance and Contravariance in Generics.- TOutput
The type the input object is to be converted to.
This type parameter is covariant. That is, you can use either the type you specified or any type that is more derived. For more information about covariance and contravariance, see Covariance and Contravariance in Generics.Parameters
- input
- TInput
The object to convert.
Return Value
The TOutput that represents the converted TInput.
Examples
This section contains two code examples. 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.
Example 1
The following code example defines a method named PointFToPoint that converts a PointF structure to a Point structure. 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. 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. 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}
Example 2
The following code example defines a method named PointFToPoint that converts a PointF structure to a Point structure. 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. 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. 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}
Remarks
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.
Extension Methods
| GetMethodInfo(Delegate) |
Gets an object that represents the method represented by the specified delegate. |
