A range variable used as an argument - vba

I'm writing a VBA function that outputs a range object. After I initialize the range object, I have trouble trying to use said object further as an argument (or, property). Here is what I'm trying to do:
Set HelpRange = Worksheets("sheet1").Cells(StartRow + Counter, StartCol) 'works fine
Worksheets("sheet1").HelpRange.something ...
I'm obviously aiming for worksheets(a).range(b), how can I do this when range(b) is a variable? It's obviously not working my way.

Related

Used named ranges in VBA

from1,from2,from3,to1,to2,to3 are all pre-defined named ranges. They all have the same dimension. I'm just trying to replace all the to's with all the from's.
The following code keeps giving me a type mismatch error on this line
ThisWorkbook.Names(to_ranges(i)) = ThisWorkbook.Names(from_ranges(i))
Could someone help? Thank you!
Sub named_ranges()
Dim from_ranges() As Variant, to_ranges() As Variant
from_ranges() = Array("from_1", "from_2", "from_3")
to_ranges() = Array("to_1", "to_2", "to_3")
Dim i As Integer
For i = 0 To UBound(from_ranges)
ThisWorkbook.Names(to_ranges(i)) = ThisWorkbook.Names(from_ranges(i))
Next i
End Sub
When you define a named range you define it's scope (worksheet or workbook). So:
Range(to_ranges(i)) = Range(from_ranges(i))
Will probably work just fine as the default scope for a named range is "Workbook".
That being said, you can use the .Names object here as well, you just need to get it's .RefersToRange property otherwise you aren't copying a range, instead you are copying the default property of the Name object which is its "RefersToRange" which is just a string.
Essentially you are doing:
Names(to_ranges(i)).RefersToRange = Names(from_ranges(i)).RefersToRange
Which is incorrect.
Instead (and this is total overkill compared to the first example above):
Range(Names(to_ranges(i)).RefersToRange).Value = Range(Names(from_ranges(i)).RefersToRange).Value
And... ultimately this doesn't solve your initial concern of Name scopes (workbook vs worksheet) as the RefersToRange will be scoped as it was was defined and may still end up hitting your ActiveSheet if it improperly scoped AND left unqualified here.

Magic braces in VBA Excel

I wrote some function to add some polylines to Excel sheet. Then I've discovered strange braces behavior.
I declare and define points array as this:
Dim points As Variant
Dim sh As Shape
points = Array(Array(10.5, 10.5), Array(20.4, 20.4), Array(5.1, 30.3), Array(10.5, 10.5))
' These both do not work and I get error about wrong type (error 1004) in 2007
' and application defined error 1004 on 2010:
ActiveWorkbook.ActiveSheet.Shapes.AddPolyline points
Set sh = ActiveWorkbook.ActiveSheet.Shapes.AddPolyline(points)
' These work fine:
ActiveWorkbook.ActiveSheet.Shapes.AddPolyline (points)
Set sh = ActiveWorkbook.ActiveSheet.Shapes.AddPolyline((points))
What is the strange magic of VBA braces?
Tested in 2007 and 2010 versions.
The additional parentheses around points cause the argument to be evaluated as an expression and consequently be passed ByVal.
The act of evaluating an array can change exactly how the data is packed inside the Variant that contains it (e.g. see VBA: Remove duplicates fails when columns array is passed using a variable as an example), and if the called procedure is not very lenient about what types of arrays it can accept (which it should be), then it will raise an error.
In your case I am actually surprised that passing an evaluated (points) even works, because the documentation mentions that a 2D array of Singles is expected, and Array(Array(...), Array(...), ...) is a jagged array as opposed to a 2D array. It would appear AddPolyline is written to cope with jagged arrays too, but it only recognizes them when the Variant containing the array has a particular set of flags in it which evaluating seems to produce (e.g. it might be that the presence or absence of VT_BYREF trips its flag comparison so it fails to recognize the passed array as supported).
I would call it a bug in AddPolyline, and I would explicitly define and fill a 2D array of Single to avoid it:
Dim points(1 To 4, 1 To 2) As Single
points(1, 1) = 10.5: points(1, 2) = 10.5
points(2, 1) = 20.4: points(2, 2) = 20.4
points(3, 1) = 5.1: points(3, 2) = 30.3
points(4, 1) = 10.5: points(4, 2) = 10.5

defining code on vba excel to simplify code writing process

I am attempting to reduce the amount of clutter on my code by creating "shortcuts" if you will
For instance, I always have to type
ThisWorkBook.ActiveSheet.Range
Is there a way for me to define the above to create a less wordy macro? I have tried convert to range and string and the former returns an error (but I could still get intellisense recognize and attempt to autofill) while the string version doesnt work.
Just like in any programming language, you can use variables to store data
For example:
Dim myrange As Range: Set myrange = Sheets("Sheet1").Range("B5")
Alternatively, if you will be working with the same object multiple times, you can use the With keyword
For example. instead of writing you want to work with table every time on every new line you can do
With Sheets("Sheet1").ListObjects("Table1")
.ListRows.Add
.ListColumns(2).Range(3) = "Hello World!"
' ... and so on
End With
Also, please on a sidenote: Avoid using Select/ActiveSheet/ActiveWorkbook and so on!
More info on how to here
You can create functions or customized properties, which are always evaluated when called
Property Get pARng As Range
Set pARng = ThisWorkBook.ActiveSheet.Range
End Property
Function fARng As Range
Set fARng = ThisWorkBook.ActiveSheet.Range
End Function
'Usage
Sub xxx
'...
pARng.Rows(1).Activate
'Same as ThisWorkBook.ActiveSheet.Range.Rows(1).Activate
fARng.Rows(1).Activate
'using function instead achieves same result
End Sub

Why must Set be used to hold objects?

While working on my PowerPoint macro, I noticed the following:
To obtain the current, active slide:
Dim currSlide As Slide
Set currSlide = Application.ActiveWindow.View.Slide
To obtain a newly created Textbox:
Dim textbox As Shape
Set textbox = currSlide.Shapes.AddTextbox(...)
I'm new to VBA, having worked with Java, C++ & C#. Why must Set be used above? Why does using Slide & Shape instead generate errors? In what way is VBA different in how variable declaration work in this respect?
This is taken from Byte Comb - Values and References in VBA
In VBA, the difference between value types and reference types is made explicit by requiring the keyword Set when assigning a reference. In addition, you will often see assigning a reference referred to as “binding”.
Byte Comb goes into great detail about the inter working of the VBA. I highly recommend that any serious about programming using the VBA read through it.
In layman's terms: Set is used so that the compiler knows that the programming wants to have a variable reference an Object type. In this way, the compiler will know to throw an error when you are trying to assign a value to an object.
Another reason is that objects can have default values.
In this example I have a variable named value that is of a Variant type. Variants can be of any type in the VBA. Notice how the compiler knows that to assign the value of the Range when value = Range("A1") and to set a reference to the Range when the keyword Set is used in Set value = Range("A1").

Returning the Default Property

I fill A1 and A2 as follows:
I then run:
Sub WhatIsGoingOn()
Dim r As Range, sh As Worksheet
Set r = Range(Cells(1, 1))
Set sh = Sheets(Cells(2, 1))
End Sub
I expected that in both cases, VBA would use the default property of Cells (the Value) property to Set each variable. However I get a runtime error 13 on the last line of code!
In order to avoid errors, I must use:
Sub WhatIsGoingOn2()
Dim r As Range, sh As Worksheet
Set r = Range(Cells(1, 1))
Set sh = Sheets(Cells(2, 1).Value)
End Sub
What is going on here ??
The difference is in how the input to their default properties is handled by the implementation of the Range and Sheets objects.
The default property of both the Range and the Sheets object takes a parameter of type Variant. You can pass anything to it, so no type coercion will be necessary. In your first example you pass a Range object to both.
How the default properties handle the input is up to themselves. Apparently the property of the Range tries to retrieve the default value of the passed parameter, in your example an address as String. The Sheets object doesn't seem to be so forgiving and raises an error because you neither passed a number nor a String.
Inconsistency is one of the strengths of VBA...
Btw., passing CStr(Cells(2, 1)) would also work, because you explicitly cast to String before passing as a parameter.
Perhaps Leviathan's comment that "Inconsistency is one of the strengths of VBA..." may ring true, but there are some contextual details that his answer neglects (and is technically incorrect on some subtle points). He is correct that for the given code that all of the parameters are variants, but the statement that "no type coercion will be necessary" can be misleading and perhaps just wrong in many cases. Even if many objects and methods are programmed to handle multiple types and default values, this very question reveals that it is a mistake to avoid purposely ensuring (or coercing) the correct data type. Avoiding default properties altogether (by always typing out the full reference) can avoid many headaches.
A significant difference between the lines of code for this particular question is this: Range is a property that takes parameters, while Sheets is also a property but has no parameters. Range and Sheets are NOT objects in this context, even though they are properties which do return Range and Sheets objects, respectively. They are properties of an (automatic global) object defined for the particular module or Excel workbook instance. This detail is not trivial for understanding what the code is actually doing.
The Obect Browser in the VBA window reveals the following metadata for the two properties:
Property Range(Cell1, [Cell2]) As Range
Property Sheets As Sheets
For Range(Cells(1, 1)), the argument Cells(1,1) is passed to the parameter Cell1. Cells itself is a property of the Excel.Global hidden object and it returns a Range object, so that Cells(rowindex, colindex) is calling a hidden default property of the Range class equivalent to Cells._Default(rowindex, colindex). The return type of the property _Default() is not declared, so technically it could return any type in a variant, but inspection shows that it returns a Range object. Apparently passing a Range object to its default property will attempt to take the default value and if it is a valid range value, like a string with a range expression, then it will execute without error.
The default property for the Sheets class is the parameterized hidden _Default(Index) method. Thus, Sheets(Cells(2, 1)) is equivalent to Sheets._Default(Cells(2, 1)). More importantly, it means that Sheets._Default(Cells(2, 1)) is passing a Range object as an index value, but documentation says that it expects an integer or string value. We already mentioned that the index parameter is variant... and when passing an object to a variant, it always passes the actual object and never its default property. So we know that Sheets.Item obtains a Range object in that call. Here is were Levithan was correct in that Sheets.Item can decide what to do with it. It is likely that it could have been smart enough to get the single string value and continue without error. Other collection objects (with a default Item(index) property) in MS Office objects do not seem to exhibit this same "pickiness", so it appears that Sheets._Default() (and perhaps Sheets.Item()) is being rather strict on validating its arguments. But this is just a particular design issue with this method only... not necessarily an overall issue with VBA.
What can be difficult is determining exactly what the source objects of the properties are. Inside the ThisWorkbook module, Me.Sheets reveals that Sheets is a property of the particular Workbook for the module. But Me.Range is not valid in the Workbook module, but right-clicking on the Range property (without the Me qualifier) and choosing "Definition" results in the message "Cannot jump to Range because it is hidden". However, once in the Object Browser, righ-clicking within the browser one can choose "Show Hidden Members" which will then allow navigating to the hidden Global objects and other hidden members.
Why the inconsistency and the hidden properties? In an attempt to make the current instance of Excel and all of its components accessible in a "natural" way, Excel (and all Office applications) implement these various hidden properties to avoid the "complexity" of having to repeatedly discover and type out full references. For instance, the automatic global Application object also has both Range and Sheets properties. Actual documentation for Application.Sheets, for example, says "Using this property without an object qualifier is equivalent to using ActiveWorkbook.Sheets". Even that documentation fails to say is that ActiveWorkbook is in turn a property of the global Excel Application object'.