Visual Basic - Ascertain number of fields in a user defined type

Author

Ascertain number of fields in a user defined type

Carl Imthurn

2006-01-27, 6:56 pm

Is there a way to ascertain at run time how many "fields" are in a particular user-defined type?

For example:

Public Type DrugSummaryItem
ProcedureNumber As String
HowMany As Integer
End Type

Public DrugSummaryArray() As DrugSummaryItem

How do I ascertain that the array DrugSummaryArray() has exactly 2 fields in it?
And, even better, what data type they are?

Thanks in advance --

Carl Imthurn

Ken Halter

2006-01-27, 6:56 pm

"Carl Imthurn" <nospam@all.com> wrote in message
news:OspWiL4IGHA.648@TK2MSFTNGP14.phx.gbl...
> Is there a way to ascertain at run time how many "fields" are in a
> particular user-defined type?
>

No way that I've heard of... unless it's a Public type and you're using
tlbinf32.dll to query its interfaces. If that's the case, it'll show the
members and types just like VBs Object Browser does (since tlbinf32.dll is
what the Object Browser uses to inspect components)

--
Ken Halter - MS-MVP-VB - Please keep all discussions in the groups..
DLL Hell problems? Try ComGuard - http://www.vbsight.com/ComGuard.htm
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Dmitriy Antonov

2006-01-27, 9:55 pm

"Carl Imthurn" <nospam@all.com> wrote in message
news:OspWiL4IGHA.648@TK2MSFTNGP14.phx.gbl...
> Is there a way to ascertain at run time how many "fields" are in a
> particular user-defined type?
>
> For example:
>
> Public Type DrugSummaryItem
> ProcedureNumber As String
> HowMany As Integer
> End Type
>
> Public DrugSummaryArray() As DrugSummaryItem
>
> How do I ascertain that the array DrugSummaryArray() has exactly 2 fields
> in it?
> And, even better, what data type they are?
>
> Thanks in advance --
>
> Carl Imthurn
>

Perhaps I don't understand the task, but, I would say, it is guaranteed by
compiler. So it is ascertained "by definition". So it will always have the
number of members and their types as it was declared and there is no way to
do it otherwise. What else you need to ascertain?

Dmitriy.

Carl Imthurn

2006-01-30, 6:55 pm

Thank you both for your replies -- here's some additional information
that I should have included in the initial post -- my apologies . . .

I am populating a data entry form from one of nine arrays. Each array contains a user-defined type as follows:

> Public Type DrugSummaryItem
> ProcedureNumber As String
> HowMany As Integer
> End Type
>
> Public DrugSummaryArray() As DrugSummaryItem

Each user-defined type contains between 2 and 5 fields. Those fields could be string or date datatype.
What is the possibility of determining the number of fields/columns in a UDT so that I would know
how many controls to put on the data entry form? I can hard-code a value in a table, but if it could be
determined at runtime that would be great.

Thanks again --

Carl

Lance Wynn

2006-01-30, 6:55 pm

Hi,

I was intrigued by this, and I know that it is done within the Soap toolkit
to create the WSDL from a COM component. I'm not sure if this is how they
do it, but I was able to use the following code to interrogate the dll, find
UDTs, and List their elements with datatypes. you need to create a
reference to the TypeLib Information library, and then just paste this code,
and run the test sub. You'll want to add error handling, and all, but maybe
this will get you started.

Lance

Option Explicit

Function TypeLibUDTs(sFileName As String) As Variant
Dim oTypeLib As TLI.TypeLibInfo
Dim oTypeInfo As TLI.TypeInfo
Dim i As Long, j As Long

Set oTypeLib = CreateObject("TLI.TypeLibInfo")
oTypeLib.ContainingFile = sFileName

If oTypeLib.TypeInfoCount Then
For i = 1 To oTypeLib.TypeInfoCount
Set oTypeInfo = oTypeLib.TypeInfos(i)
If oTypeInfo.TypeKind = TKIND_RECORD Then
Debug.Print "---UDT found: " & oTypeInfo.Name
For j = 1 To oTypeInfo.Members.Count
Debug.Print "UDT Element Name: " & oTypeInfo.Members(j).Name
Debug.Print "UDT DataType : " &
oTypeInfo.Members(j).ReturnType.VarType
Next
End If
Next
End If

Set oTypeLib = Nothing

End Function

Sub Test()
TypeLibUDTs "c:\UDTTypeLibTest.dll"
End Sub

"Carl Imthurn" <nospam@all.com> wrote in message
news:ObEZpAbJGHA.3944@tk2msftngp13.phx.gbl...
Thank you both for your replies -- here's some additional information
that I should have included in the initial post -- my apologies . . .

I am populating a data entry form from one of nine arrays. Each array
contains a user-defined type as follows:

> Public Type DrugSummaryItem
> ProcedureNumber As String
> HowMany As Integer
> End Type
>
> Public DrugSummaryArray() As DrugSummaryItem

Each user-defined type contains between 2 and 5 fields. Those fields could
be string or date datatype.
What is the possibility of determining the number of fields/columns in a UDT
so that I would know
how many controls to put on the data entry form? I can hard-code a value in
a table, but if it could be
determined at runtime that would be great.

Thanks again --

Carl

Carl Imthurn

2006-01-30, 6:55 pm

Wow.
Thanks Lance - I really appreciate the time you took to do this.
I will check it out as soon as I can and report back.

Carl

Lance Wynn wrote:

> Hi,
>
> I was intrigued by this, and I know that it is done within the Soap toolkit
> to create the WSDL from a COM component. I'm not sure if this is how they
> do it, but I was able to use the following code to interrogate the dll, find
> UDTs, and List their elements with datatypes. you need to create a
> reference to the TypeLib Information library, and then just paste this code,
> and run the test sub. You'll want to add error handling, and all, but maybe
> this will get you started.
>
> Lance
>
> Option Explicit
>
> Function TypeLibUDTs(sFileName As String) As Variant
> Dim oTypeLib As TLI.TypeLibInfo
> Dim oTypeInfo As TLI.TypeInfo
> Dim i As Long, j As Long
>
> Set oTypeLib = CreateObject("TLI.TypeLibInfo")
> oTypeLib.ContainingFile = sFileName
>
> If oTypeLib.TypeInfoCount Then
> For i = 1 To oTypeLib.TypeInfoCount
> Set oTypeInfo = oTypeLib.TypeInfos(i)
> If oTypeInfo.TypeKind = TKIND_RECORD Then
> Debug.Print "---UDT found: " & oTypeInfo.Name
> For j = 1 To oTypeInfo.Members.Count
> Debug.Print "UDT Element Name: " & oTypeInfo.Members(j).Name
> Debug.Print "UDT DataType : " &
> oTypeInfo.Members(j).ReturnType.VarType
> Next
> End If
> Next
> End If
>
> Set oTypeLib = Nothing
>
>
> End Function
>
> Sub Test()
> TypeLibUDTs "c:\UDTTypeLibTest.dll"
> End Sub
>
>
>
> "Carl Imthurn" <nospam@all.com> wrote in message
> news:ObEZpAbJGHA.3944@tk2msftngp13.phx.gbl...
> Thank you both for your replies -- here's some additional information
> that I should have included in the initial post -- my apologies . . .
>
> I am populating a data entry form from one of nine arrays. Each array
> contains a user-defined type as follows:
>
>
> Each user-defined type contains between 2 and 5 fields. Those fields could
> be string or date datatype.
> What is the possibility of determining the number of fields/columns in a UDT
> so that I would know
> how many controls to put on the data entry form? I can hard-code a value in
> a table, but if it could be
> determined at runtime that would be great.
>
> Thanks again --
>
> Carl
>
>

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