How to use instance of New Object in With... Block

Question

Dim objects As New List(Of Object)
With New Object
   .prop1 = "Property 1"
   .prop2 = "Property 2"
    objects.add(.instance) 'i mean instance of New Object
End With

is it possible.

I ask new question because last question has mislead information and I don't give right answer. so here code.

You already asked pretty much this exact question a couple of days ago: http://stackoverflow.com/questions/24361003/how-to-use-me-in-vb-net-with-end-with-block — jmcilhinney, Jun 26 '14 at 05:40

jmcilhinney · Accepted Answer · 2014-06-26T09:18:01.750

No it is not possible. The With statement basically creates an implicit variable. All you can do with that variable is access members and there is no member that returns a reference to the object itself.

If you want succinct code to create, populate and add an object to a list then do this:

myList.Add(New SomeType With {.SomeProperty = someValue,
                              .SomeOtherProperty = someOtherValue})

Interestingly, you can make it work the way you wanted if you create your own extension method. I was under the impression that you could not extend the Object class but either I was wrong or that has changed because I just tried in VB 2013 and it worked. You can write a method like this:

Imports System.Runtime.CompilerServices

Public Module ObjectExtensions

    <Extension>
    Public Function Self(Of T)(source As T) As T
        Return source
    End Function

End Module

and then do something like this:

With New SomeType
    .SomeProperty = someValue
    .SomeOtherProperty = someOtherValue
    myList.Add(.Self())
End With

I'm not sure that that really provides any benefit though, given the availability of the object initialiser syntax that I demonstrated first.

Hmmm... I just realised that that's not actually extending the Object class. It was my original intention to try to do so but then I realised that a generic method was better because it would then return the same type as you call it on. I did just test it with a non-generic method extending type Object and it did still worked though.

score 0 · Answer 2 · answered Jun 26 '14 at 05:40

You should to create your own class By example :

Public Class Car
Private _NumberCar As Integer
Public Property NumberCar() As Integer
    Get
        Return _NumberCar
    End Get
    Set(ByVal value As Integer)
        _NumberCar = value
    End Set
End Property


Private _ColorCar As Color
Public Property ColorCar() As Color
    Get
        Return _ColorCar
    End Get
    Set(ByVal value As Color)
        _ColorCar = value
    End Set
End Property


Private _OwnerName As String
Public Property OwnerName() As String
    Get
        Return _OwnerName
    End Get
    Set(ByVal value As String)
        _OwnerName = value
    End Set
End Property
End Class

and in the Class where you want to add the cars object do this :

    Dim CarList As New List(Of Car)
    Dim item As New Car
    With item
        .NumberCar = 1243
        .ColorCar = Color.Red
        .OwnerName = "Ibra"
    End With
    CarList.Add(item)

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How to use instance of New Object in With... Block

2 Answers2