You probably heard that Visual Studio 2008 lets you select the target framework version so you can use it to compile .NET 2.0 applications. I suspect you also heard about all the new cool features VB 9 includes like stuff like LINQ etc. Just in case you didn't make sure you read up on Overview of Visual Basic 9.0 by Erik Meijer, Amanda Silver, and Paul Vick.
And you probably assumed all those cool new features would only work if you where targeting the 3.5 framework, I know I did 
. Well guess again! Some of these features are only syntactic sugar completely handled by the VB compiler.
Some of the features you can use are implicitly typed variables, both with simple and complex types.
Dim aValue = 1
'aValue = "Demo"
Console.WriteLine(aValue)
Note that assigning a string to aValue produces a compile error!
Dim home As
New Country With {.Name = "the Netherlands"}
Another nice thing you can use is the new short notation for nullable types.
Dim aNullableInt As
Integer?
aNullableInt = Nothing
And best of all is Lambda expressions! All they are is syntactic sugar and the compiler can take care of them. So much nicer than before
Dim countries As
New List(Of Country)
countries.Add(home)
countries.Add(New Country With {.Name = "France"})
countries.Add(New Country With {.Name = "Belgium"})
Dim found = countries.Find(Function(c As Country) c.Name = "France")
And just to show what is actually happening behind the scene below is the code as decompiled using Reflector.
<StandardModule()> _
Friend
NotInheritable
Class Module1
' Methods
<DebuggerStepThrough, CompilerGenerated> _
Private
Shared
Function _Lambda$__1(ByVal c As Country) As
Boolean
Return (c.Name = "France")
End
Function
<STAThread()> _
Public
Shared
Sub Main()
Dim aValue As
Integer = 1
Console.WriteLine(aValue)
Dim VB$t_ref$S0 As
New Country
VB$t_ref$S0.Name = "the Netherlands"
Dim home As Country = VB$t_ref$S0
Dim countries As
New List(Of Country)
countries.Add(home)
VB$t_ref$S0 = New Country
VB$t_ref$S0.Name = "France"
countries.Add(VB$t_ref$S0)
VB$t_ref$S0 = New Country
VB$t_ref$S0.Name = "Belgium"
countries.Add(VB$t_ref$S0)
Dim found As Country = countries.Find(New Predicate(Of Country)(AddressOf Module1._Lambda$__1))
End
Sub
End
Class
Note that the compiler generated a Lambda function in this case because I used a constant string in the search filter. If I had used a variable it would have generated the required closure as an embedded type.
Enjoy VB9!
