Problems with constructors

[hog]

I am coming up against this problem on a regular basis which makes me think Im not understanding the constructor theory too well.

Im sur eyou will see the problem as soon as you read .....

Public New(ByVal lngEquipmentID as Long)

Public New(ByVal blnLiveRecords as Boolean)

Public New(ByVal strSupplierName as String)

Yup, its the ole narrowing conversion thingy. Is there a way around this as Im having to invent stupid ways to get around it like this, which is rediculous!!

Public New(ByVal lngEquipmentID as Long)

Public New(ByVal blnLiveRecord as Boolean, ByVal strAnyCrap as String)

Thnx

 

[ailzaj]

Public Sub New()      default constructor
        m_CustID = 1
        m_Name = "Michael"
End Sub

Public Sub New(ByVal CustID As Integer, ByVal Name As String)
        m_CustID = CustID
        m_Name = Name
        m_NoCustomers = m_NoCustomers + 1    Read only property
End Sub

Does this help?

ailzaj

 

[hog]

Erm no? Doesnt make sense to me??

 

[Nerseus]

I didnt see a question in your original post - what seems to be the problem/issue/question?

Maybe you forgot the word Sub in your constructor, as in:

Public [b]Sub[/b] New(ByVal lngEquipmentID As Long)
instead of
Public New(ByVal lngEquipmentID As Long)

-Nerseus

 

[hog]

Ooops!

Public Sub New(ByVal lngEquipmentID As Long)
Public SubNew(ByVal blnLiveRecords As Boolean)
Public Sub New(ByVal strSupplierName As String)

The problem I get is when I compile I get a message saying without a narrowing conversion. Basically I think it is complaining that Long, Boolean and string can all pass the same value and it doesnt know which constructor to call?

 

[dsgreen57]

Understand what you are saying.. one way probably round it is to rethink what your class is doing, and whether constructors in that format are necessary.

You would have to explain the purpose of each constructor for me to make a judgement on that... but if indeed all your constructors do have a valid purpose and it doesnt make sense to design them in a different way; I dont know off the top of my head away of combatting the problem you describe but will look into it.

 

[hog]

OK,

Public Sub New(ByVal lngEquipmentID As Long)

This allows me to create an Equipment object based on the EquipmentID selected by the user from a combobox

Public Sub New(ByVal blnLiveRecords As Boolean)

This creates an Equipment object that contains either all live equipment or all archived equipment based on the boolean value. The method objEquipment.RecordSource is used to as the source data in reports.

Public Sub New(ByVal strSupplierName As String)

This creates an Equipment object based on the supplier name selected by the user

 

[ailzaj]

Are you using option strict?

What code have you got in the constructors?

ailzaj

 

[hog]

Alas, no Im not :-(

I did loads of code prior to realising this! When I try to add option strict I get error messages all over the place!

 

[Heiko]

That could be the problem.
We *are* using option strict and we do the stuff you described and we do not get the errors.

 

[Divil]

You should always use Option Strict.

 

[dsgreen57]

You need to explicitly cast variables as passing them to the constructor if they are of another type other than defined within the constructor.

The compiler will then be able to determine, which constructor you are trying to call.

 

[jfackler]

Are you sure its not a problem with your class member variables?
Seems you may be trying to assign a variable an inappropriate value when the constructor is passing the parameter.
Thus the narrowing conversion error.

Jon

 

[hog]

Mmm me thinks Im going to have to spend time getting the option strict to work to see if this resolves it.

Ill keep ya posted....thanks for the tips