How to create a type-safe, collection class that supports For Each...Next?

[Andrew J. Marshall]

It was SO easy in VB6. Add a few methods, set a few funky properties and
*BAM*, type-safe collection class that supports the For Each...Next syntax.

I've been trying to do this in VB.NET with little success.

I started inherting DictionaryBase because of the Key retrieval ability, but
my code bombed on the For Each line because I had Option Strict On and the
types didn't match. I now loop with an Object and then use CType, but that's
BS! >8-(

Do I need to create my own Enumerator and overload Current()?

C'mon Generics!!!

Thanks in advance for help,
Andrew J. Marshall
MCP (Visual Basic)
Fairfax, VA

[The Howler]

Try this..

(It is a collection of ContractSale objects). It will support the For...Each that you requir

Public Class ContractSale
Inherits CollectionBas

Public Function Add(ByVal strBranchNo As String, ByVal intTillNo As Integer,
ByVal strReceiptNo As String, ByVal strCompositeRec eiptNo As String,
ByVal intContractID As Integer, ByVal strBarcode As String,
ByVal dteSaleDate As Date, ByVal strSurname As String,
ByVal strMobileNo As String, ByVal strIMEI As String,
ByVal strSIM As String,
ByVal strNetwork As String, ByVal strImageFileNam e As String) As ContractSal

Dim objNew As New ContractSal

With objNe
.BranchNo = strBranchN
.TillNo = intTillN
.ReceiptNo = strReceiptN
.CompositeRecei ptNo = strCompositeRec eiptN
.ContractID = intContractI
.Barcode = strBarcod
.SaleDate = dteSaleDat
.Surname = strSurnam
.MobileNo = strMobileN
.IMEI = strIME
.SIM = strSI
.Network = strNetwor
.ImageFileName = strImageFileNam
End Wit

list.Add(objNew
Add = objNe

End Functio
Public Sub Remove(ByVal intIndex As Integer
list.RemoveAt(i ntIndex
End Su

Public ReadOnly Property Item(ByVal intIndex As Integer) As ContractSal
Ge
Return CType(list.Item (intIndex), ContractSale
End Ge
End Propert

End Clas
----- Andrew J. Marshall wrote: ----

It was SO easy in VB6. Add a few methods, set a few funky properties an
*BAM*, type-safe collection class that supports the For Each...Next syntax

I've been trying to do this in VB.NET with little success

I started inherting DictionaryBase because of the Key retrieval ability, bu
my code bombed on the For Each line because I had Option Strict On and th
types didn't match. I now loop with an Object and then use CType, but that'
BS! >8-

Do I need to create my own Enumerator and overload Current()

C'mon Generics!!

Thanks in advance for help
Andrew J. Marshal
MCP (Visual Basic
Fairfax, V

[Nick Hall]

The DictionaryBase enumerator returns DictionaryEntry objects rather than
the objects you store in the collection. This allows you to have a
reference both to the object and its associated with key. So, to use
For-Each with a DictionaryBase-derived class you need to do something
similar to the following: -

For each de as DictionryEntry in MyCollection
Dim item as MyClass = DirectCast(de.C urrent, MyClass)

'....Use as necessary
Next de

Nick Hall
"Andrew J. Marshall" <An************ *@ObjectVision. netANTISPAMDEVI CE> wrote
in message news:%2******** ********@TK2MSF TNGP11.phx.gbl. ..

It was SO easy in VB6. Add a few methods, set a few funky properties and
*BAM*, type-safe collection class that supports the For Each...Next syntax.
I've been trying to do this in VB.NET with little success.

I started inherting DictionaryBase because of the Key retrieval ability, but my code bombed on the For Each line because I had Option Strict On and the
types didn't match. I now loop with an Object and then use CType, but that's BS! >8-(

Do I need to create my own Enumerator and overload Current()?

C'mon Generics!!!

Thanks in advance for help,
Andrew J. Marshall
MCP (Visual Basic)
Fairfax, VA

[Andrew J. Marshall]

Howler,

Thanks!

I actually started with CollectionBase, but I needed access to items by a
key so I switched to DictionaryBase. Any thoughts?

Andrew J. Marshall
MCP (Visual Basic)
Fairfax, VA

"The Howler" <an*******@disc ussions.microso ft.com> wrote in message
news:E0******** *************** ***********@mic rosoft.com...

Try this...

(It is a collection of ContractSale objects). It will support the For...Each that you require
Public Class ContractSales
Inherits CollectionBase

Public Function Add(ByVal strBranchNo As String, ByVal intTillNo As Integer, _ ByVal strReceiptNo As String, ByVal strCompositeRec eiptNo As String, _ ByVal intContractID As Integer, ByVal strBarcode As String, _ ByVal dteSaleDate As Date, ByVal strSurname As String, _ ByVal strMobileNo As String, ByVal strIMEI As String, _ ByVal strSIM As String, _
ByVal strNetwork As String, ByVal strImageFileNam e As String) As ContractSale
Dim objNew As New ContractSale

With objNew
.BranchNo = strBranchNo
.TillNo = intTillNo
.ReceiptNo = strReceiptNo
.CompositeRecei ptNo = strCompositeRec eiptNo
.ContractID = intContractID
.Barcode = strBarcode
.SaleDate = dteSaleDate
.Surname = strSurname
.MobileNo = strMobileNo
.IMEI = strIMEI
.SIM = strSIM
.Network = strNetwork
.ImageFileName = strImageFileNam e
End With

list.Add(objNew )
Add = objNew

End Function
Public Sub Remove(ByVal intIndex As Integer)
list.RemoveAt(i ntIndex)
End Sub

Public ReadOnly Property Item(ByVal intIndex As Integer) As ContractSale Get
Return CType(list.Item (intIndex), ContractSale)
End Get
End Property

End Class

----- Andrew J. Marshall wrote: -----

It was SO easy in VB6. Add a few methods, set a few funky properties and *BAM*, type-safe collection class that supports the For Each...Next syntax.
I've been trying to do this in VB.NET with little success.

I started inherting DictionaryBase because of the Key retrieval ability, but my code bombed on the For Each line because I had Option Strict On and the types didn't match. I now loop with an Object and then use CType, but that's BS! >8-(

Do I need to create my own Enumerator and overload Current()?

C'mon Generics!!!

Thanks in advance for help,
Andrew J. Marshall
MCP (Visual Basic)
Fairfax, VA