VB6 Runtime Type Retrieval - vb6

How can you obtain the Type (the name as a string is sufficient) of an Object in VB6 at runtime?
i.e. something like:
If Typeof(foobar) = "CommandButton" Then ...
/EDIT: to clarify, I need to check on Dynamically Typed objects. An example:
Dim y As Object
Set y = CreateObject("SomeType")
Debug.Print( <The type name of> y)
Where the output would be "CommandButton"

I think what you are looking for is TypeName rather than TypeOf.
If TypeName(foobar) = "CommandButton" Then
DoSomething
End If
Edit: What do you mean Dynamic Objects? Do you mean objects created with
CreateObject(""), cause that should still work.
Edit:
Private Sub Command1_Click()
Dim oObject As Object
Set oObject = CreateObject("Scripting.FileSystemObject")
Debug.Print "Object Type: " & TypeName(oObject)
End Sub
Outputs
Object Type: FileSystemObject

TypeName is what you want... Here is some example output:
VB6 Code:
Private Sub cmdCommand1_Click()
Dim a As Variant
Dim b As Variant
Dim c As Object
Dim d As Object
Dim e As Boolean
a = ""
b = 3
Set c = Me.cmdCommand1
Set d = CreateObject("Project1.Class1")
e = False
Debug.Print TypeName(a)
Debug.Print TypeName(b)
Debug.Print TypeName(c)
Debug.Print TypeName(d)
Debug.Print TypeName(e)
End Sub
Results:
String
Integer
CommandButton
Class1
Boolean

I don't have a copy of VB6 to hand, but I think you need the
Typename()
function... I can see it in Excel VBA, so it's probably in the same runtime. Interestingly, the help seems to suggest that it shouldn't work for a user-defined type, but that's about the only way I ever do use it.
Excerpt from the help file:
TypeName Function
Returns a String that provides information about a variable.
Syntax
TypeName(varname)
The required varname argument is a
Variant containing any variable except
a variable of a user-defined type.

This should prove difficult, since in VB6 all objects are COM (IDispatch) things. Thus they are only an interface.
TypeOf(object) is class probably only does a COM get_interface call (I forgot the exact method name, sorry).

Related

BASIC runtime error. Argument is not optional

I could not figure out whats the problem is
Sub Reportstart(oEvent As Object)
Dim oFeld As Object
Dim oForm As Object
Dim oDocument As Object
Dim oDocView As Object
Dim Arg()
oField = oEvent.Source.Model
oForm = oField.Parent
sURL = oForm.DataSourceName
oDocument = StarDesktop.loadComponentFromURL(sURL, "C:\Users\Nameless\Desktop\Latest.odb", 0, Arg() )
oDocView = oDocument.CurrentController.Frame.ContainerWindow
oDocView.Visible = False
oDocument.getCurrentController().connect
Wait(100)
oDocument.ReportDocuments.getByName("report_student").open
oDocument.close(True)
End Sub'
The error is BASIC runtime error.
Argument is not optional.
Reportstart requires an argument oEvent, and the way you executed it, the subroutine was not given any argument.
The macro was designed to be called from an event handler of a control, for example, the Execute action of a push button on a Base form. Perhaps you executed the subroutine from the LibreOffice Basic IDE instead.
Related: https://ask.libreoffice.org/en/question/192344/argument-is-not-optional/

callbyname vb6 using string as argument

I am trying to set some images's visibility to false by using CallByName and a loop through the objects.
here is the code
Private Sub command1Click
dim theobj_str as string
dim ctr as integer
for ctr = 1 to 3
theobj_str = "Images" & ctr
CallByName theobj_str, "Visible", vbLet,False
end for
END SUB
It throws an error "TYPE MISMATCH" on "CallByName **theobj_str**..."
The CallByName takes an object as its first argument. I need to somehow convert the string "theobj_str" into an object. How can I do this ?
The CallByName works fine if I call it like : CallByName Images2, "Visible", vbLet,False
Thanks
If you don't need to use CallByName you could loop through the controls collection and check the type. If the type matches the control you want to hide then you can set it's visible property that way.
The code would look like this:
Private Sub Command_Click()
SetControlVisibility "Image", False
End Sub
Private Sub SetControlVisibility(ByVal controlType As String, ByVal visibleValue As Boolean)
Dim ctrl As Control
For Each ctrl In Me.Controls
If TypeName(ctrl) = controlType Then
ctrl.Visible = visibleValue
End If
Next
End Sub
Doing it this way will allow you to add more image controls to your form without having to remember to change your counts in the for loop.
Hope that helps.

VBScript Function as Parameter, or similar Construct

I'm trying to put together tests in HP Unified Functional Testing
the way a programmer would.
For those unaware, the tool uses VBScript as its driver.
Because I want to use data from the same DataTable across multiple UFT actions
-- and because the Global table already has a different set of data on it
-- I want to retrieve data from an external file.
UFT happily supports this function.
My current plan is that, depending on which test I'm running,
I will iterate through only a range of rows in that table.
This is the script I've come up with:
' targets the local sheet, but
' not the same value as dtLocalSheet
Const sheetNum = 2
dim sheetRowCount
DataTable.ImportSheet "PersonFile.xlsx", 1, sheetNum
sheetRowCount = DataTable.GetSheet(sheetNum).GetRowCount
dim firstRow, lastRow
firstRow = Parameter("FirstPersonIndex")
lastRow = Parameter("LastPersonIndex")
If sheetRowCount < lastRow Then
lastRow = sheetRowCount
End If
If sheetRowCount >= firstRow Then
Dim i
For i = firstRow To lastRow
DataTable.SetCurrentRow i
' begin payload
MsgBox(DataTable.Value("LastName", dtLocalSheet))
' end payload
Next
End if
I don't want to have to repeat all this boilerplate
every time I want to use this pattern.
I'd really like to have something like:
In a Function Library:
sub LoopThroughSheetAnd(sheetFile, doThis)
' targets the local sheet, but
' not the same value as dtLocalSheet
Const sheetNum = 2
dim sheetRowCount
DataTable.ImportSheet sheetFile, 1, sheetNum
sheetRowCount = DataTable.GetSheet(sheetNum).GetRowCount
dim firstRow, lastRow
firstRow = Parameter("FirstRow")
lastRow = Parameter("LastRow")
If sheetRowCount < lastRow Then
lastRow = sheetRowCount
End If
If sheetRowCount >= firstRow Then
Dim i
For i = firstRow To lastRow
DataTable.SetCurrentRow i
call doThis()
Next
End if
end sub
In the original action...
sub Payload1()
MsgBox(DataTable.Value("LastName", dtLocalSheet))
end sub
LoopThroughSheetAnd "PersonFile.xlsx", Payload1
In a separate action, 3 or 4 steps later...
sub Payload2()
' compare the data against another data source
end sub
LoopThroughSheetAnd "PersonFile.xlsx", Payload2
The above code doesn't work in VBScript.
A type mismatch error is thrown
as soon as we try to pass Payload1 as a parameter.
How could one reasonably pull this off in VBScript?
Bonus points if the answer also works in UFT.
You can pass functions as parameters with the GetRef() function. Here's a utility map function, like you'd find in JavaScript that accepts an array and calls a function for each element of the array:
Sub Map(a, f)
Dim i
For i = 0 To UBound(a)
' Call a function on each element and replace its value with the function return value
a(i) = f(a(i))
Next
End Sub
Map MyArray, GetRef("SomeFunc")
Now you could write SomeFunc so that it operates on a value and returns an updated value:
Function SomeFunc(i)
SomeFunc = i + 1
End Function
This works fine. map calls SomeFunc using the function "pointer" we passed to it.
You could do something similar with your LoopThroughStreetAnd function:
LoopThroughStreetAnd "PersonFile.xlsx", GetRef("Payload2")
The standard way of callbacks in VBScript uses GetRef, as in this demo.
When using objects, you can wrap a call to a method in an object, and then you can pass the object. (This is approximately what happens in other languages already, you just have to do it manually in VBScript.)
The only issue is that any method called this way has to be Public.
I would use a naming scheme of something like "Func1", "Func2", "Action1", "Action2", etc., depending on the arity of the functions and whether they return values or not.
Dim s : Set s = New Something : s.Run
Class Something
Public Sub HowToPassMe(pValue)
WScript.Echo pValue
End Sub
Public Sub Run
Dim action : Set action = New Action1Wrapper
Set action.Target = Me
Dim se : Set se = New SomethingElse
se.DoSomethingElse action
End Sub
End Class
Class SomethingElse
Public Sub DoSomethingElse(pAction1)
pAction1.Action1("something")
End Sub
End Class
Class Action1Wrapper
Private mTarget
Public Property Set Target(value) : Set mTarget = value : End Property
Public Sub Action1(p1)
mTarget.HowToPassMe(p1)
End Sub
End Class
Using Execute, Action1Wrapper can also be written something like the following. You can also write a factory class for easier use.
Class Action1Wrapper
Private mTarget
Public Property Set Target(value) : Set mTarget = value : End Property
Private mName
Public Property Let Name(value) : mName = value : End Property
Public Sub Action1(p1)
Execute "mTarget." & mName & "(p1)"
End Sub
End Class
Class Action1Factory_
Public Function Create(pTarget, pName)
Dim a1 : Set a1 = New Action1Wrapper
Set a1.Target = pTarget
a1.Name = pName
Set Create = a1
End Function
End Class
Dim Action1Factory : Set Action1Factory = New Action1Factory_
Used as:
Dim action : Set action = Action1Factory.Create(Me, "HowToPassMe")
Dim se : Set se = New SomethingElse
se.DoSomethingElse action
And as I write the question, my memory gets jogged,
and I begin researching a "feature" I once discovered.
This fails to work in the context of HP UFT,
but if you're running cscript, or working with Classic ASP,
you can either declare a function late, or replace a previous declaration,
to change how it works.
VBScript lets you declare the same function or subroutine
multiple times in a program.
It treats the last declaration as the correct one.
You can get around this in cscript and ASP by physically separating
the different versions of the function,
so that one doesn't get clobbered by the other.
You'll have to be careful not to put the two anywhere near each other,
or you(r successor) might have an aneurysm trying to debug the outcome.
Honestly, you're probably better served refactoring your code some other way.
Now, with the disclaimers out of the way,
the following example is for use with cscript or wscript.
Code
Since this won't work in UFT anyway, I'll write from scratch.
In WrapperSub.vbs:
' Sub WrapperSub_Payload doesn't exist in this file.
' It must be declared by the calling file or the program will crash.
Sub WrapperSub()
wscript.echo("This begins the wrapper.")
WrapperSub_Payload
wscript.echo("This ends the wrapper.")
End Sub
In WrapperSubUseA.vbs:
With CreateObject("Scripting.FileSystemObject")
call ExecuteGlobal(.openTextFile("WrapperSub.vbs").readAll())
End With
Sub WrapperSub_Payload
wscript.echo("This is payload A.")
End Sub
WrapperSub
In WrapperSubUseB.vbs:
With CreateObject("Scripting.FileSystemObject")
call ExecuteGlobal(.openTextFile("WrapperSub.vbs").readAll())
End With
Sub WrapperSub_Payload
wscript.echo("This is payload B.")
End Sub
WrapperSub
Output
>cscript wrappersubusea.vbs
Microsoft (R) Windows Script Host Version 5.8
Copyright (C) Microsoft Corporation. All rights reserved.
This begins the wrapper.
This is payload A.
This ends the wrapper.
>cscript wrappersubuseb.vbs
Microsoft (R) Windows Script Host Version 5.8
Copyright (C) Microsoft Corporation. All rights reserved.
This begins the wrapper.
This is payload B.
This ends the wrapper.
Note that if a placeholder for WrapperSub_Payload
were declared in the source file,
that placeholder would always execute instead of the intended subroutine.
This is probably due to ExecuteGlobal
executing after the current file is parsed,
causing the placeholder to load after the local declaration.
When you try this in UFT --
placing the contents of WrapperSub.vbs in a function library --
the function library rightfully ignores the caller's scope.
It will then fail because WrapperSub_Payload doesn't exist in scope.

vb6, variable not defined for Label using Module

Sorry to ask such a dumb question.. but for the life of me i cant get it.. i have searched EVERYWHERE... This is a Re-Creation of my code that gives the same error. This is the most basic example i could re-create.
I dont understand why i have to declare a Label ?? (or an object)
What I am trying to accomplish is use my main form to call all the modules.
This is the FORM
'frmMain.frm
Option Explicit
Public Sub btnOpen_Click()
GetNum
End Sub
This is the MODULE
'modGet.bas
Option Explicit
Public Sub GetNum()
Dim a As String
Dim b As String
a = "hello"
b = "world"
-> Label1.Caption = a 'ERROR, Compile Error, Variable not Defined. (vb6)
Label2.Caption = b
End Sub
YES, i have a form, with a Button named 'btnOpen', i have 2 Labels named 'Label1' & 'Label2'
If i ADD..
Dim Label1 As Object 'in MODULE
i get a different error..
ERROR '91' Object Variable or With block variable not set
IF I put everything in 1 FORM, it works..(but i want to use separate modules)
I Commented out 'OPTION EXPLICIT' ... same error.
In another Test, i got the error for a TextBox..
TextBox1.Text = x
Once i get the answer for this, i can apply it for everything... I'm sure it's simple too and imma feel stupid. :-(
One of my Main Things is Querying WMI, and i get the ERROR '91' for the Label (This is in a For Each Loop) .. But its the same error, its like its makin me Declare Objects..(using Modules)
Label1.Caption = objItem.Antecedent
If Someone Could PLEASE Help me...
Use
form1.label1.caption = a
But make sure form1 is loaded
You get the error because Label1 and Label2, and your other controls for that matter do not exist in the scope of modGet.bas. They can only be referenced (the properties accessed or set), from with the form. The different error you get when you add Dim Label1 As Object is caused because an you defined Label1 as an Object, not as a Label, and an object does not have a Caption property. Unless you have a good reason for putting the GetNum sub in a .bas module move it into the form and it should work.
I modified the second example. It will modify the strings passed into it in a way that when execution passes back to the form you can assign the strings to your textboxes. I am against modifying controls on a form from another module because it goes against the idea of encapsulation.
'modGet.bas
Option Explicit
Public Function GetHello() As String
Dim strHello As String
strHello = "Hello"
GetHello = strHello
End Function
'frmMain.frm
'Option Explicit
Public Sub btnOpen_Click()
Label1.Caption = GetHello()
End Sub
Something a little different.
'MyModule.bas
Public Sub HelloWorld ByRef Value1 As String, ByVal Value2 As String)
On Error GoTo errHelloWorld
Value1 = "Hello"
Value2 = "World"
Exit Sub
errHelloWorld:
' deal with the error here
End Sub
'frmMain.frm
Option Explicit
Private Sub frmMain_Load()
Dim strText1 As String
Dim strText2 As String
HelloWorld(strText1, strText2)
Text1.Text = strText1
Text2.Text = strText2
End Sub
I also added basic error handling in the second example

Control Properties in Visual Basic 6

Is there a way to ask for a control property in a loop??
I need somethig like this:
For each p in control.properties
if p = "Value" then
msgbox "I Have Value Property"
elseif p = "Caption" then
msgbox "I Have Caption Property"
end if
next
It could be done somehow?
Found this code on Experts Exchange. Add a reference to TypeLib Information.
Public Enum EPType
ReadableProperties = 2
WriteableProperties = 4
End Enum
Public Function EnumerateProperties(pObject As Object, pType As EPType) As Variant
Dim rArray() As String
Dim iVal As Long
Dim TypeLib As TLI.InterfaceInfo
Dim Prop As TLI.MemberInfo
On Error Resume Next
ReDim rArray(0) As String
Set TypeLib = TLI.InterfaceInfoFromObject(pObject)
For Each Prop In TypeLib.Members
If Prop.InvokeKind = pType Then
iVal = UBound(rArray)
rArray(iVal) = UCase$(Prop.Name)
ReDim Preserve rArray(iVal + 1) As String
End If
Next
ReDim Preserve rArray(UBound(rArray) - 1) As String
EnumerateProperties = rArray
End Function
You can ask for a list of the readable, or writeable properties.
Bonus, ask if a specific property exists.
Public Function DoesPropertyExist(pObject As Object, ByVal _
PropertyName As String, pType As EPType) As Boolean
Dim Item As Variant
PropertyName = UCase$(PropertyName)
For Each Item In EnumerateProperties(pObject, pType)
If Item = PropertyName Then
DoesPropertyExist = True
Exit For
End If
Next
End Function
Beaner has given an excellent direct answer to the question you have asked.
I'm guessing what you might be trying to do. Perhaps you're trying to get the "text" from a control but you don't know the type of the control at runtime. You could consider something like this, which tries a number of hard-coded property names in turn until something works.
Function sGetSomeText(ctl As Object) As String
On Error Resume Next
sGetSomeText = ctl.Text
If Err = 0 Then Exit Function
sGetSomeText = ctl.Caption
If Err = 0 Then Exit Function
sGetSomeText = ctl.Value
If Err = 0 Then Exit Function
sGetSomeText = "" 'Nothing worked '
End Function
Another approach would be to check the type of the control at runtime. You can use
If TypeName(ctl) = "whatever" or
If TypeOf ctl Is whatever.
Then you could switch to code for specific control types that definitely have the Text property, etc.
I'm not sure what you're hoping to accomplish, but I'm pretty sure VB6 does not support what you're talking about. You could try something like this:
If control.Value Is Not Nothing Then
msgbox "I Have Value Property"
Else If control.Caption Is Not Nothing Then
msgbox "I Have Caption Property"
See if that accomplishes what you're looking to do.

Resources