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Array of objects + For Each = Error? - 3/12/2008 6:41:49 AM
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obiwaynekenobi
Posts: 2
Score: 0
Joined: 3/12/2008
Status: offline
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I normally work with ASP.NET, not Classic, but my current position has a legacy ASP application (poorly written) that I'm trying to refactor. I'm looking at modularizing the code and using OOP techniques - I have a sample class that sets a few basic properties of a Customer entity, and uses the ActiveRecord pattern to return an array of all of them.
When I try to iterate though the collection using a simple For Each loop, and display the object's properties, VBScript complains.
My code is as follows:
' Customer class
Class Customer
Private m_idCustomer ' As Integer
Private m_name ' As String
Private m_lastName ' As String
Public Function Create(id, name, lastName)
m_idCustomer = id
m_name = name
m_lastName = lastName
End Function
Public Property Get ID ' As Integer
ID = m_idCustomer
End Property
Public Property Get Name ' As String
Name = m_name
End Property
public property get LastName ' As String
LastName = m_lastName
end property
Public Function FindAll() ' As Array
Dim aryCustomers()
Set rs = DbManager.ExecuteStatement("SELECT TOP 10 idCustomer, name, lastName FROM customers")
If Not rs.EOF Then
ReDim aryCustomers(rs.RecordCount)
While Not rs.EOF
For i = 0 To (UBound(aryCustomers) - 1)
Set c = New Customer
Call c.Create(rs("idCustomer"), rs("name"), rs("lastName"))
Set aryCustomers(i) = c
rs.MoveNext
Next
Wend
End If
FindAll = aryCustomers
End Function
End Class
<!-- This is in the calling page -->
Set someCust = New Customer
custList = someCust.FindAll()
For Each cust In custList
Response.Write "ID: " & cust.ID & "<br />"
Response.Write "First Name: " & cust.Name & "<br />"
Response.Write "Last Name: " & cust.LastName & "<hr />"
Next
----
This seems to be pretty simple, and I'm not sure why VBScript is complaining. The exact error I get points to the "For Each cust In custList" line, with the specific error being "Object required: cust" - clearly, VBScript isn't setting cust to be a Customer object, and is trying to call a property on a String. However, I get it to work when I use a normal For..Next loop (e.g. "For i = 0 To UBound(custList) - 1"), and when I use custList(i) instead of cust. While it's not a big deal, I Prefer the For Each syntax; I think it's cleaner and more natural to use.
Can I do what I want to in VBScript, or am I stuck using For i = 0 To UBound(custList) - 1? As I said, I'm not really familiar with VBScript, but I'm trying to clean up the horrendous codebase I've "inherited" - the previous programmer didn't indent anything, used cryptic variable names, and made gratuitious use of On Error Resume Next to make sure that his code worked (in other words, if I remove it, the code dies with some nonsense error like calling a method on an item that hasn't been created yet, because it's created twenty lines further down the page).
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RE: Array of objects + For Each = Error? - 3/12/2008 7:29:41 AM
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obiwaynekenobi
Posts: 2
Score: 0
Joined: 3/12/2008
Status: offline
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Well, mainly because I'm trying to properly encapsulate things - I'm used to C#/VB.NET and ASP.NET, so I'm used to having an entity class wrap the database calls, so the page can deal with natural properties of the model, instead of knowing it's using a RecordSet. I mean, I could use the recordset, it's mainly a semantic thing. The current code is full of recordset calls (usually with names such as rTemp and rsTemp), and I find it hard to follow the flow. Also, the data doesn't really explain what columns are often, the previous dev used a lot of abbreviations, so it's more natural to use product.PartNumber than rs("mfr_numb")
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RE: Array of objects + For Each = Error? - 3/12/2008 7:35:07 AM
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ebgreen
Posts: 4408
Score: 29
Joined: 7/12/2005
Status: online
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All valid points. I still don't see anything in your code that would explain the error. Gimme a while and I will try to recreate it if I can since I still don't see anything glaringly obvious.
_____________________________
"... when you are good and crazy, oooh, oooh, oooh, the sky is the limit!" - The Tick
Goog places to start:http://www.visualbasicscript.com/m_24727/tm.htm
http://www.visualbasicscript.com/m_47117/tm.htm
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RE: Array of objects + For Each = Error? - 3/12/2008 8:53:52 AM
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TNO
Posts: 974
Score: 10
Joined: 12/18/2004
From: thenewobjective.com
Status: offline
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Out of curiosity, what is the VarType of custList?
Here's my wild theory (take with a grain of salt):
For Each cust In custList
In this structure cust can only be a variant, generic object, or Automation object IF custList is an object collection (which an Array is not). If custList is an Array like in this case, cust can ONLY be a variant type hence throwing the exception "Object required: cust".
So my theoretical solution:
For Each cust In custList
Set cust.........
< Message edited by TNO -- 3/12/2008 8:58:32 AM >
_____________________________
Consolidated Script Component: Now in Testing stage!
A universe of complexity...
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RE: Array of objects + For Each = Error? - 3/13/2008 5:06:10 AM
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ebgreen
Posts: 4408
Score: 29
Joined: 7/12/2005
Status: online
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Ok so this bothered me. I have found a way to give you For Each access to all the items. It isn't exactly what you were doing but it does put you on familiar ground. The workaround is to use an arraylist. Here is sample straight vbs code but I can't see any reason why it wouldn't work in asp as long as any version of the .Net framework is present wherever it is running.
Dim oOuterFoo
Dim alOuterAL
Dim oItem
Set oOuterFoo = New Foo
Set alOuterAL = oOuterFoo.FindAll()
For Each oItem In alOuterAL
WScript.Echo oItem.Index & " -> " & oItem.Value
Next
Class Foo
Private nIndex
Private strValue
Public Property Get Index
Index = nIndex
End Property
Public Property Get Value
Value = strValue
End Property
Public Function Create(nInd, strVal)
nIndex = nInd
strValue = strVal
End Function
Public Function FindAll()
Dim i
Dim oFoo
Dim alOut : Set alOut = CreateObject("System.Collections.ArrayList")
For i = 1 To 5
Set oFoo = New Foo
Call oFoo.Create(i, "Value " & i)
alOut.Add oFoo
Next
Set FindAll = alOut
End Function
End Class
_____________________________
"... when you are good and crazy, oooh, oooh, oooh, the sky is the limit!" - The Tick
Goog places to start:http://www.visualbasicscript.com/m_24727/tm.htm
http://www.visualbasicscript.com/m_47117/tm.htm
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RE: Array of objects + For Each = Error? - 3/13/2008 6:45:44 AM
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TNO
Posts: 974
Score: 10
Joined: 12/18/2004
From: thenewobjective.com
Status: offline
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Would the Dictionary object work as well?
_____________________________
Consolidated Script Component: Now in Testing stage!
A universe of complexity...
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RE: Array of objects + For Each = Error? - 3/13/2008 7:16:35 AM
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ebgreen
Posts: 4408
Score: 29
Joined: 7/12/2005
Status: online
|
Not for what the OP is trying to do. To make it work you would have to make the key some index value and the value the customer object. That in itself would not be as clean as an array or arraylist but even worse would be the retrieval. It would look like this:
For Each cust In custList.Keys
Response.Write "ID: " & custList(cust).ID & "<br />"
Response.Write "First Name: " & custList(cust).Name & "<br />"
Response.Write "Last Name: " & custList(cust).LastName & "<hr />"
Next
Which just isn't as clean as I think the OP wanted.
_____________________________
"... when you are good and crazy, oooh, oooh, oooh, the sky is the limit!" - The Tick
Goog places to start:http://www.visualbasicscript.com/m_24727/tm.htm
http://www.visualbasicscript.com/m_47117/tm.htm
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