C# 4 and .NET 4

OC186 ❘ ChaPTer 53 c#, visuAl bAsic, c++/cli, And f#
End Sub
End Class
'...
Dim evd As New EventDemo()
Dim subscr As New Subscriber()
AddHandler evd.DemoEvent, AddressOf subscr.Handler
evd.FireEvent()
code snippet VisualBasic/EventDemo.vb
Visual Basic offers another syntax that is not available with the other languages: you can also use the
Handles keyword with the method that subscribes to the event. The requirement for this is to define a
variable with the WithEvents keyword:
Public Class Subscriber
Public WithEvents evd As EventDemo
Public Sub Handler(ByVal x As Integer) Handles evd.DemoEvent
' Handler implementation
End Sub
Public Sub Action()
evd = New EventDemo()
evd.FireEvent()
End Sub
End Class
generiCs
All four languages support the creation and use of generics. Generics are discussed in Chapter 5,
“Generics.”
To use generics, C# borrowed the syntax from C++ templates to define the generic type with angle brackets.
C++/CLI uses the same syntax. In Visual Basic, the generic type is defined with the Of keyword in braces.
Here, F# looks very similar to C#:
// C#
List intList = new List();
intList.Add(1);
intList.Add(2);
intList.Add(3);
// C++/CLI
List^ intList = gcnew List();
intList->Add(1);
intList->Add(2);
intList->Add(3);
code snippet CSharp/GenericsDemo.cs
code snippet CPPCLI/GenericsDemo.h
' Visual Basic
Dim intList As List(Of Integer) = New List(Of Integer)()
intList.Add(1)
intList.Add(2)
intList.Add(3)
code snippet VisualBasic/GenericsDemo.vb
// F#
let intList =
new List()
intList.Add(1)
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