Option Strict On disallows late binding in VB6 migrated code

Question

I have migrated a VB6 control to Vb.Net and when I had option strict on, I am getting "Option Strict On disallows late binding" error. Below I have mentioned VB6 code as well as migrated code in detail.

VB6 Code:-

Private m_colRows As Collection    'Represents the rows in a table
Private m_lngCurrCol As Long 'Control variable for Col Property
Private m_lngCurrRow As Long 'Control variable for Row Property

Public Property Let CellText(ByVal strText As String)
     m_colRows(m_lngCurrRow)(m_lngCurrCol).Text = strText
End Property
Public Property Get CellText() As String
   CellText = m_colRows(m_lngCurrRow)(m_lngCurrCol).Text
End Property

Below is the Migrated code(Vb.Net)

Public Property CellText() As String
    Get
        CellText = m_colRows.Item(m_lngCurrRow)(m_lngCurrCol).Text
    End Get
    Set(ByVal Value As String)
        m_colRows.Item(m_lngCurrRow)(m_lngCurrCol).Text = Value
    End Set
End Property

Option Strict On disallows late binding and I need help on modifying the code to work with it on.

@steve :- I have defined like this :- Private m_colRows As Collection — vandy
If Item returns an object, you need to cast it to it's proper class. — the_lotus

supercat supercat · Accepted Answer · 2018-10-22T15:00:21

The VB6 Collection type holds references of type Object. If you wish to use the .Text method on members thereof, you will either have to change ColRows into a generic collection (e.g. a List(Of Control()) or else convert the references held in it into Control references before use (e.g.

Public Property CellText() As String
    Get
        CellText = CType(m_colRows.Item(m_lngCurrRow), Control())(m_lngCurrCol).Text
    End Get
    Set(ByVal Value As String)
        CellText = CType(m_colRows.Item(m_lngCurrRow), Control())(m_lngCurrCol).Text = Value
    End Set
End Property

Without seeing more of your code, I can't tell which approach would be easier and/or would yield better results. I would guess that using a generic collection would likely yield cleaner code, but the VB6-style Collection type supports some constructs that the generic ones generally don't, including the ability to modify the collection during enumeration, which can sometimes make porting tricky.

Option Strict On disallows late binding in VB6 migrated code

2 Answers