VS 2008 Extension methods

[Lloyd Sheen]

Is it possible to create extension methods based on the generic. Not the
best description so I will expand.

If I have several lists e.g.

dim list1 as list(of object1)
dim list2 as list(of object2) etc.

Can I define an extension method such that it can be used for all List(of
T)?

LS

 

[Tom Shelton]

Is it possible to create extension methods based on the generic. Not the
best description so I will expand.

If I have several lists e.g.

dim list1 as list(of object1)
dim list2 as list(of object2) etc.

Can I define an extension method such that it can be used for all List(of
T)?

LS

Sure, make it generic:

Option Strict On
Option Explicit On

Imports System.Runtime.CompilerServices

Module Module1

Sub Main()
Dim l1 As New List(Of Integer)
Dim l2 As New List(Of String)

For i As Integer = 1 To 10
l1.Add(i)
Next

l2.Add("this is a test")
l2.Add("another entry")

Console.WriteLine(l1.MyCount())
Console.WriteLine(l2.MyCount())
End Sub

<Extension()> _
Public Function MyCount(Of T)(ByVal l As List(Of T)) As Integer
Return l.Count
End Function

End Module

HTH

 

[Lloyd Sheen]

Sure, make it generic:

Option Strict On
Option Explicit On

Imports System.Runtime.CompilerServices

Module Module1

Sub Main()
Dim l1 As New List(Of Integer)
Dim l2 As New List(Of String)

For i As Integer = 1 To 10
l1.Add(i)
Next

l2.Add("this is a test")
l2.Add("another entry")

Console.WriteLine(l1.MyCount())
Console.WriteLine(l2.MyCount())
End Sub

<Extension()> _
Public Function MyCount(Of T)(ByVal l As List(Of T)) As Integer
Return l.Count
End Function

End Module

HTH

Thanks Tom, works great. Will have to get my head around the syntax.

LS