How to perform object initializer for a list property in VB.NET

Question

I am trying to implement object initializer. All the classes are already created by someone else. I cannot change.

I have a class Ins.vb that has a list as a property

Partial Public Class Ins
 Private itemField As Item1
 Private sizeCodeListField() As SizeCode 'This is the property
 Public Property Item() As Item1
 Get
 Return Me.itemField
 End Get
 Set
 Me.itemField = value
 End Set
 End Property
 Public Property SizeCodeList() As SizeCode()
 Get
 Return Me.sizeCodeListField
 End Get
 Set
 Me.sizeCodeListField = value
 End Set
 End Property
End Class

Item1.vb

Public Partial Class Item1
 Private codeField As String
 
 Public Property Code() As String
 Get
 Return Me.codeField
 End Get
 Set
 Me.codeField = value
 End Set
 End Property
End Class

SizeCode.vb

Partial Public Class SizeCode
 Private sizeCode1Field As String
 Private sizeCodeDescriptionField As String
 Public Property SizeCode1() As String
 Get
 Return Me.sizeCode1Field
 End Get
 Set
 Me.sizeCode1Field = value
 End Set
 End Property
 Public Property SizeCodeDescription() As String
 Get
 Return Me.sizeCodeDescriptionField
 End Get
 Set
 Me.sizeCodeDescriptionField = value
 End Set
 End Property
End Class

This is how I am trying to do object initialization

Dim myVar = New Ins _
 With {.Item = New Item1 With {.Code = "I"},
 .SizeCodeList = New SizeCode With {.SizeCode1 = "S", .SizeCodeDescription = "Description"}} 'I am getting an error here

The error is Value of type 'SizeCode' cannot be converted to 'SizeCode()'

I am not sure how to implement this and I am stuck.

• Craig: SizeCodeList is an array. Put braces around the New SizeCode ... expression so that you are providing an array, and it should work (you'll be assigning an array of length 1 containing the new object that you declared inline).

Answer 1

Your syntax should be something like this:

 Dim myVar = New Ins _
 With {.Item = New Item1 With {.Code = "I"},
 .SizeCodeList = New SizeCode() {New SizeCode With {.SizeCode1 = "S", .SizeCodeDescription = "Description"}}} 

• Craig: The New SizeCode() isn't necessary, VB will infer it from the array that follows.
• Misael Moneró: @Craig but it makes it cleaner

Answer 2

You are initializing .SizeCodelist as a SizeCode but it should be a list. I did not test it but this should work I think:

 Dim myVar = New Ins With
{.Item = New Item1 With {.Code = "I"},
 .SizeCodeList = New List(Of SizeCode)}
Dim newSizeCode As New SizeCode With {.SizeCode1 = "S", .SizeCodeDescription = "Description"}
myvar.SizeCodeList.add(newSizeCode)

• Craig: This wouldn't work because the member is an array, not a list.