List(Of T).ConvertAll(Of TOutput) Method (Converter(Of T, TOutput))
Converts the elements in the current List(Of T) to another type, and returns a list containing the converted elements.
Assembly: mscorlib (in mscorlib.dll)
Public Function ConvertAll(Of TOutput) ( converter As Converter(Of T, TOutput) ) As List(Of TOutput)
Parameters
- converter
-
Type:
System.Converter(Of T, TOutput)
A Converter(Of TInput, TOutput) delegate that converts each element from one type to another type.
Return Value
Type: System.Collections.Generic.List(Of TOutput)A List(Of T) of the target type containing the converted elements from the current List(Of T).
Type Parameters
- TOutput
The type of the elements of the target array.
| Exception | Condition |
|---|---|
| ArgumentNullException | converter is null. |
The Converter(Of TInput, TOutput) is a delegate to a method that converts an object to the target type. The elements of the current List(Of T) are individually passed to the Converter(Of TInput, TOutput) delegate, and the converted elements are saved in the new List(Of T).
The current List(Of T) remains unchanged.
This method is an O(n) operation, where n is Count.
The following example defines a method named PointFToPoint that converts a PointF structure to a Point structure. The example then creates a List(Of 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(Of TOutput) method. The ConvertAll(Of TOutput) 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.
Imports System 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}
Available since 2.0