Formulas to be triggered when Excel is opened or saved - vba

I have several custom-made (VBA) formulas in my Excel. Examples are
= isfileExists(c3)
= isReadOnly(c3)
There are multiple calls to these functions (200/column)
These are slowing down the file as they involve heavy VBA. I want the above formulas to be run only when user opens the file or saves the file only!
How can I go on to do this without touching 'enabling/disabling automatic calculations'? (Please note I do know how to write the event functions but I am looking for an idea to put inside them/anywhere)
Sample idea I have is, adding a ' infront the formulas and whenever user opens/saves, that ' (apostrophe) would be removed using macro; hence the formulas would calculate. Any other easier suggestions?
Thanks much!

You can cache the formula results in a Global (or Static inside the function) dictionary object: once you've checked a file once you can use the cached result instead of repeating the file check)
Public Function ExpensiveCheck(fpath As String) As Boolean
Static dict As Object, ans As Boolean
'create the dictionary if not already created
If dict Is Nothing Then
Set dict = CreateObject("scripting.dictionary")
End If
If Not dict.exists(fpath) Then
ans = (Dir(fpath, vbNormal) <> "") 'do your checking here
dict.Add fpath, ans
End If
ExpensiveCheck = dict(fpath)
End Function
The dict will be lost when the session ends, so the formula should always refresh the cache when you open the file.
Downside is you may need some mechanism to clear/refresh the cache if you want to update the output after some change in the files being checked.

If you don't want your UDFs to calculate along with the rest of the worksheet cells, then you don't want UDFs; make them Private, or stick Option Private Module at the top of the standard module where they're declared, to make them unavailable to use as custom worksheet functions.
Then handle Workbook.Open and Workbook.BeforeSave events, and have these two handlers call some Private Sub that's responsible for writing to the cells you currently have these UDFs in.
That way the values will only be computed when the workbook opens and before it's saved.
UDFs that incur disk I/O aren't ideal: keep that processing for macros.

Related

Prevent Excel from making links to external macro functions in formulas absolutely

There are two workbooks: The view foo.xlsm and the control bar.xlsm which gets loaded from the foo.xlsm with the Workbooks.Open()-Method and includes the VBA-Code necessary for the view. It does so because there are multiple possible paths to the bar.xlsm which have to be checked prior.
Set wC = Workbooks.Open("path\bar.xlsm", ReadOnly:=True, Editable:=False, AddToMru:=False)
In foo.xlsm there is a formula referencing to a macro function from bar.xlsm:
=bar.xlsm!functionName(parameter)
The problem is that on every startup excel modifies that link to the last path from which the bar.xlsm got loaded successfully, e.x.:
='C:/Users/X/Desktop/bar.xlsm'!functionName(parameter)
This behaviour is unwanted because the path of bar.xlsm can and will change. How to prevent excel from making this link absolutely?
In the meantime I have found an uncomplicated workaround. I call the desired method using a wrapper function in the view workbook:
Public Function functionWrapper() As Integer
functionWrapper = Application.Run("bar.xlsm!functionName(parameter)")
End Function
The wrapper function is called inside the desired cell formula as follows:
=functionWrapper(parameter)

How do I assign an Excel VBA variable to a Defined Name

How do I return a value from a VBA Function variable to a Defined Name in Excel 2010?
In the example below, I want i to be returned to Excel as a Defined Name Value_Count that can be reused in other formulas, such that if MsgBox shows 7, then typing =Value_Count in a cell would also return 7.
Everything else below is about what I've tried, and why I'd like to do it. If it's inadvisable, I'd be happy to know why, and if there's a better method.
Function process_control_F(raw_data As Variant)
Dim i As Integer
i = 0
For Each cell In raw_data
i = i + 1
Next cell
MsgBox i
End Function
My goal is to have the value returned by the MsgBox be returned instead to a Defined Name that can be reused in other forumulas. However, I cannot get the value to show. I have tried a variety of forms (too numerous to recall, let alone type here) similar to
Names.Add Name:="Value_Count", RefersTo:=i
I am trying to accomplish this without returning a ton of extra info to cells, just to recall it, hence the desire to return straight to a Defined Name.
I'm using a Function rather than Sub to streamline my use, but if that's the problem, I can definitely change types.
I am creating a version of a Statistical Control Chart. My desired end result is to capture a data range (generally about 336 values) and apply a series of control rules to them (via VBA), then return any values that fall outside of the control parameters to Defined Names that can then be charted or otherwise manipulated.
I've seen (and have versions of) spreadsheets that accomplish this with digital acres of helper columns leading to a chart and summary statistics. I'm trying to accomplish it mostly in the background of VBA, to be called via Defined Names to Charts — I just can't get the values from VBA to the Charts.
The interest in using a Function rather than a Sub was to streamline access to it. I'd rather not design a user interface (or use one), if I can just keystroke the function into a cell and access the results directly. However, as pointed out by Jean-François Corbett, this is quickly turning into a circuitous route to my goal. However, I still think it is worthwhile, because in the long-term I have a lot of iterations of this analysis to perform, so some setup time is worth it for future time savings.
With minor changes to your function, you can use its return value to accomplish what you want:
Function process_control_F(raw_data As Variant) As Integer ' <~~ explicit return type
Dim i As Integer
Dim cell As Variant ' <~~~~ declare variable "cell"
i = 0
For Each cell In raw_data
i = i + 1
Next cell
process_control_F = i ' <~~~~ returns the value i
End Function
You can then use that function in formulas. For example:

Storing range reference in a global variable

I'm using several named ranges located in different worksheets. I need to read from and write to those ranges in many situations throughout my VBA code.
So my question is: what is the proper way to store those range references in global variables for quick access? Or is there a better way?
I tried declaring global variables:
Public WS_BOARD As Worksheet
Public RNG_BOARD As Range
and initializing them on Workbook_Open:
Private Sub Workbook_Open()
Set WS_BOARD = Worksheets("BOARD")
Set RNG_BOARD = WS_BOARD.Range("NR_BOARD")
End Sub
This works okay except that if my code crashes those global variables are reset to Nothing and cannot be used any further (i.e. in worksheet event handlers).
Of course, I can always use something like
Worksheets("BOARD").Range("NR_BOARD")
everywhere in my code but I think it will affect performance because it obviously needs to lookup objects using string names, let alone it being not DRY.
One way is to "load" them once into memory and then pass them as arguments into other subs/functions.
Passing Variables By Reference And By Value
Second, you can declare them as module-scope variables (something like public, but only in the module you declare them).
Scope of variables in Visual Basic for Applications
Third, your way.
Scope of variables in Visual Basic for Applications
Every worksheet has a Name property (the tab caption) and a CodeName property. If you use the CodeName in your code, you don't need a variable. Like a userform, a sheet's code name is auto instantiated when you use it. Select the worksheet under your project in the Project Explorer (Ctrl+R), go to the Propeties (F4) and change the (Name) to a meaninful CodeName. The Project Explorer will then show the sheet as
wshDataEntry (Data Entry)
if you made the CodeName wshDataEntry and the tab said Data Entry.
For Ranges, I used defined names in the spreadsheet. It's like a global variable that never goes out of scope. If you have, say, and interest rate cell that you need to read in various procedure, name it Interest_Rate. Then at the top of every procedure where you need it
Set rInterest = wshDataEntry.Range(gsNMINTEREST)
where gsNMINTEREST is a global string variable holding "Interest_Rate". If the cell ever moves, you only need to move your named range for the code to work. If you change the name to "LiborPlusFour" you only need to update your global variable. Pretty DRY.
Yes there is a slight performance hit making VBA look up the named range every time. I wouldn't worry about that unless you've calculated a performance problem and identified it as the drag.
One way that I keep global variables (of course I'm very judicious using them) in scope is an Initialize procedure.
Public Sub Initialize()
If gclsApp Is Nothing Then
Set gclsApp = New CApp
'do some other setup
End If
End Sub
Then I call the Initialize procedure at the top of any module I need it. If it's Not Nothing, then it doesn't reset the variable. I'm not sure the performance implications of checking for Nothing and just looking up a named range, though.
Global variables are generally not a good idea. In some cases they're necessary, but this isn't one of those cases.
I don't think you should worry about the performance impact of looking up a few ranges by their string name. I have sheets with hundreds of named ranges, and I have never, ever observed this having a negative impact on performance.
Do you have specific evidence indicating that this is slowing down your code? If not, then don't waste time worrying about it.
I often do this to define ranges:
Type RangesType
board As Range
plank As Range
wood As Range
End Type
Function GetRanges() As RangesType
With GetRanges
Set .board = Range("board")
Set .plank = Range("plank")
Set .wood = Range("wood")
End With
End Function
Then I use them like this:
Sub something()
Dim rngs As RangesType: rngs = GetRanges
rngs.board = "My favourite board"
rngs.wood = "Chestnut"
'etc.
End Sub
Yes, ranges will get fetched by their name repeatedly if you have many subs, and no, this isn't likely to have any noticeable effect on performance.

Directly referencing userform entry in VBA instead of passing value to a variable

folks. I am new to programming, but I am writing some macros to help manage a shared Excel workbook for my job.
I am implementing a few different user roles for people who need to access this workbook. The security is not very critical, just to prevent people from accidentally making (and saving) changes to things they shouldn't be. I am just having a UserForm prompt for the password and, based on what's entered, grant the proper access.
I have it written so that the user's entry into textbox on the UserForm is referenced directly as Me.textboxPasswordEntry.Value for any comparisons. It occurs to me that this may not be best practice, but I can't put my finger on why. Maybe I'm just over thinking? At the same time, it seems silly and wasteful to declare a variable, pass the value to the variable, and then analyze that.
The Sub below is from the UserForm, and I've included it to show you what I mean. This is a very straight-forward scenario, I know, but am I courting trouble if I continue this practice through more complex ones? If so, what kind of problems might I run into?
Thanks.
Private Sub buttonOK_adminPW_Click()
'The subs SetUserType_[level] are in the ChangeUserType module
'AdminPass and DesignPass are module-level variables set on UserForm initialization
'Default user type is User. Read-only access.
'Admins can edit the workbook, but must save via a macro to ensure
' things are reset properly for Users (some sheets hidden, etc.)
'Designers can edit the workbook, but also have full ability to save using
' the regular file menu/ctrl+s/etc.
Application.ScreenUpdating = False
Select Case Me.textboxPasswordEntry.Value
Case AdminPass
'Shows right control buttons and unlocks the wkbk for admin access
SetUserType_admin
Unload Me
Case DesignPass
'Shows all control buttons and unlocks the wkbk for designer access
SetUserType_design
Unload Me
Case Else
MsgBox ("Password incorrect. Please retry.")
With Me.textboxPasswordEntry
.Value = ""
.SetFocus
End With
End Select
Application.ScreenUpdating = True
End Sub
Yeah I've also pondered over "best practise" with userforms over the years... I guess it's just through experience that I use approach below most often:
Use as little code as possible in the userform itself (thinking
is, the form is more "reusable" if it does as little as possible
back to its parent... its reason for existance is just to get input)
Do use code on the "activate" event of the form to clear all the
fields on the form (this makes sense to be in the form because then
you don't need to remember every control on the form to clear at
every point you use it)
Either directly reference objects from
the form in your calling code (i.e. stPassword =
userform1.tbPassword.value) or...
Use "public" variables in the
userform ... i.e. before all code in userform declare "public stPasswordInput as string" then you can reference in your calling code with e.g. stPassword = userform1.stPasswordInput
I'm keen to see what other people suggest though!

Execute a user-defined function into another cell VBA Excel

I need to automatize a process which execute various (a lot) user-defined function with different input parameters.
I am using the solution of timer API found in I don't want my Excel Add-In to return an array (instead I need a UDF to change other cells) .
My question is the following: "Does anybody can explain to me HOW IT IS WORKING?" If I debug this code in order to understand and change what I need, I simply go crazy.
1) Let say that I am passing to the public function AddTwoNumbers 14 and 45. While inside AddTwoNumber, the Application.Caller and the Application.Caller.Address are chached into a collection (ok, easier than vectors in order not to bother with type). Application.Caller is kind of a structured object where I can find the function called as a string (in this case "my_function"), for example in Application.Caller.Formula.
!!! Nowhere in the collection mCalculatedCells I can find the result 59 stored.
2)Ok, fair enough. Now I pass through the two UDF routines, set the timers, kill the timers.
As soon as I am inside the AfterUDFRoutine2 sub, the mCalculatedCell(1) (the first -- and sole -- item of my collection) has MAGICALLY (??!?!?!!!??) obtained in its Text field exactly the result "59" and apparently the command Set Cell = mCalculatedCells(1) (where on the left I have a Range and on the right I have ... I don't know) is able to put this result "59" into the variable Cell that afterward I can write with the .Offset(0,1) Range property on the cell to the right.
I would like to understand this point because I would like to give MORE task to to inside a single collection or able to wait for the current task to be finished before asking for a new one (otherwise I am over-writing the 59 with the other result). Indeed I read somewhere that all the tasks scheduled with the API setTimer will wait for all the callback to be execute before execute itself (or something like this).
As you can see I am at a loss. Any help would be really really welcomed.
In the following I try to be more specific on what (as a whole)
I am planning to achieved.
To be more specific, I have the function
public function my_function(input1 as string, Field2 as string) as double
/*some code */
end function
I have (let's say) 10 different strings to be given as Field2.
My strategy is as follow:
1)I defined (with a xlw wrapper from a C++ code) the grid of all my input values
2)define as string all the functions "my_function" with the various inputs
3)use the nested API timer as in the link to write my functions IN THE RIGHT CELLS as FORMULAS (not string anymore)
3)use a macro to build the entire worksheet and then retrieve the results.
4)use my xlw wrapper xll to process further my data.
You may wonder WHY should I pass through Excel instead of doing everything in C++. (Sometime I ask myself the same thing...) The prototype my_function that I gave above has inside some Excel Add-In that I need to use and they work only inside Excel.
It is working pretty well IN THE CASE I HAVE ONLY 1 "instance" of my_function to write for the give grid of input. I can even put inside the same worksheet more grids, then use the API trick to write various different my_functions for the different grids and then make a full calculation rebuild of the entire worksheet to obtain the result. It works.
However, as soon as I want to give more tasks inside the same API trick (because for the same grid of input I need more calls to my_function) I am not able to proceed any further.
After Axel Richter's comment I would like to ad some other information
#Axel Richter
Thank you very much for your reply.
Sorry for that, almost surely I wasn't clear with my purposes.
Here I try to sketch an example, I use integer for simplicity and let's say that my_function works pretty much as the SUM function of Excel (even if being an Excel native function I could call SUM directly into VBA but it is for the sake of an example).
If I have these inputs:
input1 = "14.5"
a vector of different values for Field2, for instance (11;0.52;45139)
and then I want to write somewhere my_function (which makes the sum of the two values given as input).
I have to write down in a cell =my_function(14.5;11), in the other =my_function(14.5;0.52) and in a third one =my_function(14.5;45139).
These input changes any time I need to refresh my data, then I cannot use directly a sub (I think) and, in any case, as far as I understand, in writing directly without the trick I linked, I will always obtain strings : something like '=my_function(14.5;0.52). Once evaluated (for example by a full rebuild or going over the written cell and make F2 + return) will give me only the string "=my_function(14.5;0.52)" and not its result.
I tried at the beginning to use an Evaluate method which works well as soon as I write something like 14.5+0.52, but it doesn't work as soon as a function (nor a user-defined function) is used instead.
This is "as far as I can understand". In the case you can enlighten me (and maybe show an easier track to follow), it would be simply GREAT.
So far the comments are correct in that they repeat the simple point that a User-Defined Function called a worksheet can only return a value, and all other actions that might inject values elsewhere into the worksheet calculation tree are forbidden.
That's not the end of the story. You'll notice that there are add-ins, like the Reuters Eikon market data service and Bloomberg for Excel, that provide functions which exist in a single cell but which write blocks of data onto the sheet outside the calling cell.
These functions use the RTD (Real Time Data) API, which is documented on MSDN:
How to create a RTD server for Excel
How to set up and use the RTD function in Excel
You may find this link useful, too:
Excel RTD Servers: Minimal C# Implementation
However, RTD is all about COM servers outside Excel.exe, you have to write them in another language (usually C# or C++), and that isn't the question you asked: you want to do this in VBA.
But I have, at least, made a token effort to give the 'right' answer.
Now for the 'wrong' answer, and actually doing something Microsoft would rather you didn't do. You can't just call a function, call a subroutine or method from the function, and write to the secondary target using the subroutine: Excel will follow the chain and detect that you're injecting values into the sheet calculation, and the write will fail.
You have to insert a break into that chain; and this means using events, or a timer call, or (as in RTD) an external process.
I can suggest two methods that will actually work:
1: Monitor the cell in the Worksheet_Change event:
Private Sub Worksheet_Change(ByVal Target As Range)
Dim strFunc As String strFunc = "NukeThePrimaryTargets" If Left(Target.Formula, Len(strFunc) + 1) = strFunc Then Call NukeTheSecondaryTargets End If End Sub
Alternatively...
2: Use the Timer callback API:
However, I'm not posting code for that: it's complex, clunky, and it takes a lot of testing (so I'd end up posting untested code on StackOverflow). But it does actually work.
I can give you an example of a tested Timer Callback in VBA:
Using the VBA InputBox for passwords and hiding the user's keyboard input with asterisks.
But this is for an unrelated task. Feel free to adapt it if you wish.
Edited with following requirements: It is necessary to run a user defined worksheet function, because there are addins called in this function and those work only within a Excel sheet. The function has to run multiple times with different parameters and its results have to be gotten from the sheet.
So this is my solution now:
Public Function my_function(input1 As Double, input2 As Double) As Double
my_function = input1 + input2
End Function
Private Function getMy_Function_Results(input1 As Double, input2() As Double) As Variant
Dim results() As Double
'set the Formulas
With Worksheets(1)
For i = LBound(input2) To UBound(input2)
strFormula = "=my_function(" & Str(input1) & ", " & Str(input2(i)) & ")"
.Cells(1, i + 1).Formula = strFormula
Next
'get the Results
.Calculate
For i = LBound(input2) To UBound(input2)
ReDim Preserve results(i)
results(i) = .Cells(1, i + 1).Value
Next
End With
getMy_Function_Results = results
End Function
Sub test()
Dim dFieldInput2() As Double
Dim dInput1 As Double
dInput1 = Val(InputBox("Value for input1"))
dInput = 0
iIter = 0
Do
dInput = InputBox("Values for fieldInput2; 0=END")
If Val(dInput) <> 0 Then
ReDim Preserve dFieldInput2(iIter)
dFieldInput2(iIter) = Val(dInput)
iIter = iIter + 1
End If
Loop While dInput <> 0
On Error GoTo noFieldInput2
i = UBound(dFieldInput2)
On Error GoTo 0
vResults = getMy_Function_Results(dInput1, dFieldInput2)
For i = LBound(vResults) To UBound(vResults)
MsgBox vResults(i)
Next
noFieldInput2:
End Sub
The user can input first a value input1 and then input multiple fieldInput2 until he inputs the value 0. Then the results will be calculated and presented.
Greetings
Axel