Clarification needed

Question

Hi

I need some explanation of the following code...

    Class Car
        Public id As Integer
        Public manufacturer As String
        Public color As String
    End Class

    Function GetCars() As List(Of Car)

        Dim ret = New List(Of Car)
        ret.Add(New Car With {.id = 1, .manufacturer = "Toyota", .color = "Red"})
        ret.Add(New Car With {.id = 2, .manufacturer = "Honda", .color = "Red"})

        Return ret
    End Function

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        Dim cars = GetCars()
        Dim dictionary = cars.ToDictionary(Function(c) c.id)
    End Sub


Where does the "c" in ToDictionary(Function(c) come from, and what is that?

Answer 1

Its the vb way of doing lambda expressions

In c#:

var dictionary = cars.ToDictionary(c => c.id);

the same as Dim dictionary = cars.ToDictionary(Function(c) c.id)

Don't know all the high tech jizz maybe one of the mods can chime in but I'm pretty sure thats what it means.

http://msdn.microsoft.com/en-us/library/bb531253.aspx

Thats a good microsoft link into vb.net lambdas.

Hope this helps!

P.s. you can define the c in anyway you want doesnt have to be a c e.g. Dim dictionary = cars.ToDictionary(Function(testForLambda) testForLambda.id)

Answer 2

Hi magmo,

 

How is the problem now?   I think d13mr3m1x has provided a really helpful reply. 

 

If you need any further assistance, please feel free to let me know.

 

 

Have a nice weekend!

 

 

Best Regards,
Lingzhi Sun

MSDN Subscriber Support in Forum

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