VB.net 2005 issue with using Class and KeyValuePair

Question

I have an existing VB.net program (using visual studio 2005) that uses class InventoryLocation, and has a child class InventoryItem. I would like to revise this code to use my new class InventorySequence, which has a new primary key, includes the fields from the other classes, but does not have any child classes.

The main part of my issue is that I do not understand "KeyValuePair". From what I understand, KeyValuePair has one key and one value. In InventorySequence, I have one key, but three values. Please advise - what can I use instead of KeyValuePair? See existing code I would like to change at the bottom:

Public Class InventoryLocation ' original coding
    Public Location As String = ""
    Public Items As InventoryItems
    Public Sub New(ByVal location__1 As String)
        Location = location__1
        Items = New InventoryItems()
    End Sub
End Class
Public Class InventoryLocations
    Inherits SortedList(Of String, InventoryLocation)
End Class
'----
Public Class InventoryItem  ' original coding
    Public Location As InventoryLocation
    Public Quantity As UInteger = 0
    Public Barcode As String = ""
    Public Sub New(ByVal location__1 As InventoryLocation, ByVal quantity__2 As UInteger, ByVal barcode__3 As String)
        Location = location__1
        Quantity = quantity__2
        Barcode = barcode__3
    End Sub
End Class
Public Class InventoryItems
    Inherits SortedList(Of String, InventoryItem)
End Class
'----
Public Class InventorySequence ' my coding - need new itemseq to be the primary key
    Public ItemSeq As UInteger = 0
    Public Location As String = ""
    Public Quantity As UInteger = 0
    Public Barcode As String = ""
    Public Sub New(ByVal itemseq__4 As UInteger, ByVal location__1 As String, ByVal quantity__2 As UInteger, ByVal barcode__3 As String)
        ItemSeq = itemseq__4
        Location = location__1
        Quantity = quantity__2
        Barcode = barcode__3
    End Sub
End Class
Public Class InventorySequences
    Inherits SortedList(Of String, InventorySequence)
End Class
'---------------------------- How do I replace this code to do the same thing but use my InventorySequence class?
Dim index As Integer = 0
For Each kvpLocations As KeyValuePair(Of String, InventoryLocation) In Inventory.Locations
    Dim searchLocation As InventoryLocation = kvpLocations.Value
    If searchLocation.Location = inventoryItem.Location Then
        For Each kvpItems As KeyValuePair(Of String, InventoryItem) In searchLocation.Items
            Dim searchItem As InventoryItem = kvpItems.Value
            If searchItem.Barcode = inventoryItem.Barcode Then
                Exit For
            End If
            index += 1
        Next
        Exit For
    Else
        index += searchLocation.Items.Count
    End If
Next

You probably shouldn't be [inheriting from a list](http://stackoverflow.com/q/21692193/719186). Also, use Properties in your classes instead of fields. What's with the UInteger? Just use Integer. — LarsTech, Mar 10 '17 at 16:46
You could write a collection class to implement things like `ItemsByKey()` . — Ňɏssa Pøngjǣrdenlarp, Mar 10 '17 at 16:59
The `value` can also be a `Structure` or `Class` containing three items (which is probably better than a `List(Of T)` in this case because it looks as though the three values have different types). In more recent versions of the BCL, you could also use a three-member `Tuple` to wrap the three items, but the advantage of a `Structure` or `Class` is that they retain meaningful names instead of `Item1`, `Item2`, and `Item3`. — Craig, Mar 10 '17 at 19:31

score 0 · Answer 1 · answered Mar 15 '17 at 19:31

Some good advice was given in the comments - thanks to all who posted.

I resolved this issue by created two classes, one was a Sequence class with just the ID and a SubClass value. Then, the second class was the ID and the other columns I needed. I stopped using the previously existing Class logic, and created similar logic based on my new Classes.

When using KeyValuePair, I used this Sequence ID as the key, and the subClass as the value, and then simply populated my columns from data in the subClass.

VB.net 2005 issue with using Class and KeyValuePair

1 Answers1