user defined types? (Office XP + SP1)

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Here’s the error message: [indent]

---

Only user defined types
defined in public object modules
can be coerced to or from a variant
or passed to late-bound functions

---

[/indent]User defined type – i know what that is
public object module – not sure. How is this different from a Module or a Class module?
coercion – yeah, that’s what i guess i need
Here’s some code i was playing with in a Plain Ol’ Module to try to figure this out:

Option Explicit

Public Type udt '   user defined type
    i As Integer
End Type
    
Dim x As udt
Dim anx As Variant

Public Function CreateX(i As Integer) As Variant
    x.i = i
    '   CreateX = CVar(x)   <<< doesnt work
    '   CreateX = x         <<< doesnt work
End Function

Public Sub test()
    '   anx = CreateX(42)   <<< doesnt work
    CreateX (42)
    anx = x
End Sub

A clue! A clue! A reference to a text will do!
My kingdom for a clew, already!

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I realize this is a nonresponsive comment, but why would you ever want to “coerce” a UDT to a variant? I thought the point of a UDT was its highly structured nature (I like to use arrays of them now and again). A variant is something of a mystery. Although one can interrogate a variant for its “subtype,” what can you do if you learn that VarType(x) = vbUserDefinedType? How does it help?

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I didnt start out to coerce anything! That was the msg from vba, tho.

Your questions are dead on – i’ve been asking them myself.

What the problem revolves around is the Scripting.dictionary object, for which the documentation says “you can put any kind of data into it.” I think that the dox are confusing me with their use of “any”, since i view a UDT as “any”, whereas i am thinking now that the data type must be defined in a class (maybe they screwed up and wrote ‘object’ instead of ‘class’?).

That is the hypothesis under which i shall go back and try again with the dictionary.

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My hypothesis is correct!
If I define a Class that contains two data members, like this

Option Explicit

Public anInt As Integer
Public aLong As Long

then i can use it like this

Option Explicit
    
Dim x As Class1

Public Sub PlayWithDictionaryObject2()
    Dim d As Scripting.Dictionary
    Set d = New Scripting.Dictionary
    
    Set x = New Class1
    d.Add "Athens", x    'Add some keys and items.
    d.Add "Belgrade", 0
    d.Add "Cairo", 0

Of course, the dictionary with a bunch of different kinds of data attached to it is a beast that requires special handling, which i will avoid.

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Change

anx = x

to

anx = x.i

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Thanks Howard – i think i understand it!

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Yes, UDTs can’t be used like that you have to define a class. UDTs are good for simple things but can’t be used like like the built-in data types (although you’d think they should be). The solution is to define the same data as a class and then you can use it like any other data type.

I do this a lot then use the class object inside of collections or as returns from functions. You’d define the class almost exactly like the UDT and just use it as a data type. Add a class to your project (like you add a Form or a new Module). Then type the data that makes up the new class (the new data type).

public int1 as integer
public str1 as string
public str2 as string

Now outside of this class module you can define a variable of this data type.

dim myDat as new myClass

myDat.int1 = 5
myDat.str1 = “deb”
myDat.str2 = “woody”

This works the same as any other built-in Excel object (Range, Worksheet and 1000 others). Since I use collections a lot I use this to carry around complex data. You can’t store a UDT in a collection.

Deb

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Thanks deb-

what threw me is that the language REQUIRES class data to be GLOBAL. What i expected was that class data must to be protected, if not private.

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AAAHHHH, I see… You assumed the error messages made sense They rarely do

That one threw me for quite a while too and I didn’t get why my UDT failed until I read something in a book now I almost always use classes.

Deb

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