How to correctly Public and Set a Worksheet? - vba

Public sp As Worksheet // on top of ThisWorkbook module
...
Sub one()
Set sp = Sheets("blueSky") // marked
MsgBox sp.Name
...
Sub two()
Set sp = Sheets("blueSky") // marked
MsgBox sp.Range("A1").Value
Marked line is allways the same.
So, is it possible to write the marked line only once - and where ?
I tried on Workbook.Open event - without result
I want in each Sub write only the third line - which is allways different.

If you put the followin in a module (not ThisWorkbook) you get a global Worksheet variable:
Option Explicit
Global sp As Worksheet
You can then adress it in any of the following ways in ThisWorkbook (subs one() and two() will also work in a module):
Option Explicit
Public Sub one()
Set sp = Sheets("Sheet1") '// marked
MsgBox sp.Name
End Sub
Sub two()
Set sp = Sheets("Sheet2") ' // marked
MsgBox sp.Range("A1").Value
End Sub
Private Sub Workbook_Open()
Set sp = Sheets("Sheet3")
End Sub

Related

Create and assign variables on Workbook_open, pass it to Worksheet_change

So I have a Workbook_open sub that creates Long variables when workbook is opened:
Private Sub Workbook_open()
MsgBox ("Workbook opened")
Dim i As Long
i = 68
End Sub
How would I pass the i value to a Worksheet_change sub for a particular worksheet?
Dim i inside a procedure scope makes i a local variable; it's only accessible from within the procedure it's declared in.
The idea of passing i to another procedure is very sound: it means you intend to keep variable scopes as tight as possible, and that's a very very good thing.
But in this case it's too tight, because the parameters of an event handler are provided by the event source: you need to "promote" that local variable up one scope level.
And the next tightest scope level is module scope.
You can use the Dim keyword at module level, but for consistency's sake I'd recommend using the keyword Private instead. So in the same module, declare your module-level variable:
Option Explicit
Private i As Long
Private Sub Workbook_open()
MsgBox "Workbook opened"
i = 68
End Sub
If you want to expose that variable's value beyond this module, you can expose an accessor for it:
Option Explicit
Private i As Long
Private Sub Workbook_open()
MsgBox "Workbook opened"
i = 68
End Sub
Public Property Get MyValue() As Long
'invoked when MyValue is on the right-hand side expression of an assignment,
'e.g. foo = ThisWorkbook.MyValue
MyValue = i
End Property
Now the Sheet1 module's Worksheet_Change handler can read it:
Private Sub Worksheet_Change(ByVal Target As Range)
MsgBox ThisWorkbook.MyValue
End sub
But it can't write to it, because the property is "get-only". If everyone everywhere needs to be able to read/write to it, then you might as well make it a global variable, or expose a mutator for it:
Option Explicit
Private i As Long
Private Sub Workbook_open()
MsgBox "Workbook opened"
i = 68
End Sub
Public Property Get MyValue() As Long
'invoked when MyValue is on the right-hand side expression of an assignment,
'e.g. foo = ThisWorkbook.MyValue
MyValue = i
End Property
Public Property Let MyValue(ByVal value As Long)
'invoked when MyValue is on the left-hand side of an assignment,
'e.g. ThisWorkbook.MyValue = 42; the 'value' parameter is the result of the RHS expression
i = value
End Property
For that, declare i as a Public Variable on a Standard Module like Module1 and then you can access the value of i in Sheet Change Event if it is initialized during Workbook Open Event.
On Standard Module:
Public i As Long
On ThisWorkbook Module:
Private Sub Workbook_open()
MsgBox ("Workbook opened")
i = 68
End Sub

VBA value persistence

I have a bunch of globally defined variables in my VBA (macro) script. I set values to these in a procedure in my current module. Is there any way to get these values in another procedure present in another module.
As far as variable declaration goes.
Within a sub - this is only accessible to the sub itself:
Sub LocalScope()
Dim stringVariable as string
stringVariable = "abc"
debug.print stringVariable
End Sub
Dim at the top of the module - this is accessible to any subs within the module:
Dim stringVariable as string
Sub ModuleScope()
stringVariable = "abc"
End Sub
Sub PrintString()
debug.print stringVariable
End Sub
Public at the top of the module - this is accessible to subs in all modules:
Public stringVariable as string
Sub ModuleScope()
stringVariable = "abc"
End Sub
Sub PrintString()
debug.print stringVariable
End Sub

Get values from collection in one module into combobox in userform

I have a worksheet with data in column 'EGM'. My code saves values from this column in the collection.
If there is only one value in the collection, then variable sSelectedEGM is equal to this value.
But if there is more than one values, a user should has possibility to choose only one value (I wanted to do this in the combobox) and save selected item into variable sSelectedEGM.
My problem is, that I can't get values from this collection into userform.
When my code go into useform, the error "Type mismatch" appear. My code in worksheet:
Public sSelectedEGM As String
Public vElement As Variant
Public cEGMList As New VBA.Collection
Sub kolekcjaproba()
' ===================================
' LOOP THROUGH EGMS AND WRITE THEM INTO COLLECTION
' ===================================
Dim iOpenedFileFirstEGMRow As Integer
Dim iOpenedFileLastEGMRow As Integer
Dim iOpenedFileEGMColumn As Integer
Dim iOpenedFileEGMRow As Integer
Dim sOpenedFileEGMName As String
Dim ws As Worksheet
Dim wb As Workbook
Set wb = ThisWorkbook
Set ws = wb.Worksheets(1)
iOpenedFileFirstEGMRow = Cells.Find("EGM").Offset(1, 0).Row
iOpenedFileLastEGMRow = ActiveSheet.Cells(ActiveSheet.Rows.Count, iOpenedFileFirstEGMRow).End(xlUp).Row
iOpenedFileEGMColumn = Cells.Find("EGM").Column
For iOpenedFileEGMRow = iOpenedFileFirstEGMRow To iOpenedFileLastEGMRow
sOpenedFileEGMName = Cells(iOpenedFileEGMRow, iOpenedFileEGMColumn).Value
For Each vElement In cEGMList
If vElement = sOpenedFileEGMName Then
GoTo NextEGM
End If
Next vElement
cEGMList.Add sOpenedFileEGMName
NextEGM:
Next
If cEGMList.Count = 1 Then
sSelectedEGM = cEGMList.Item(1)
ElseIf cEGMList.Count = 0 Then
MsgBox "No EGM found"
Else
Load UserForm1
UserForm1.Show
End If
End Sub
And my code in a userform (There is only a combobox on it)
Private Sub UserForm_Initialize()
For Each vElement In cEGMList
UserForm1.ComboBox1.AddItem vElement
Next vElement
End Sub
Private Sub ComboBox1_Change()
If ComboBox1.ListIndex <> -1 Then
sSelectedEGM = ComboBox1.List(ComboBox1.ListIndex)
End If
End Sub
you have to declare cEGMList and sSelectedEGM in a standard module as public and not in a worksheet module.
Or even better: create a property on the form for the collection and for the returned values. It's always better to avoid global vars wherever possible.
This is a simplified example. In the form you can define properties and methods like that:
Option Explicit
Public TestProperty As Integer
Public Sub TestMethod()
MsgBox (TestProperty)
End Sub
Public Function TestMethodWithReturn() As Integer
TestMethodWithReturn = TestProperty * 2
End Function
outside the form you can then use this as a normal property/method of the form:
Private Sub Test()
Dim retValue As Integer
UserForm1.TestProperty = 123
UserForm1.Show vbModeless
UserForm1.TestMethod
retValue = UserForm1.TestMethodWithReturn
Debug.Print retValue
End Sub

Creating A Custom Event With VBA

I'm trying struggling to understand how to create a custom event using class modules in VBA.
I've put together the simple following example. You put a value in A1 and B1 and then re activate the sheet to calculate the sum of the two and then I hoped an event would fire to warn of calculation, but nothing happens.
I'd be very grateful for any help solving this example.
Class module cCalc:
Dim m_wks As Worksheet
Public Event BeforeCalc()
Property Set Worksheet(wks As Worksheet)
Set m_wks = wks
End Property
Public Sub Calc()
Dim dVal1 As Double
Dim dVal2 As Double
With m_wks
dVal1 = .Range("A1").Value
dVal2 = .Range("B1").Value
RaiseEvent BeforeCalc
.Range("C1").Value = dVal1 + dVal2
End With
End Sub
In a module mGlobal:
Public gCalc As cCalc
In the code behind Sheet1:
Private WithEvents calcEvent As cCalc
Private Sub calcEvent_BeforeCalc()
MsgBox "About to Calc!", vbInformation
End Sub
Private Sub Worksheet_Activate()
Set gCalc = New cCalc
Set gCalc.Worksheet = ActiveSheet
gCalc.Calc
End Sub
You can't declare event-driven classes in modules. You'll need to set the cCalc reference in gModule equal to the object you declared WithEvents in Sheet1. Change your code in Sheet1 to what i wrote below and it will work:
Private WithEvents calcEvent As cCalc
Private Sub calcEvent_BeforeCalc()
MsgBox "About to Calc!", vbInformation
End Sub
Private Sub Worksheet_Activate()
Set calcEvent = New cCalc 'Instantiate the WithEvents object above
Set mGlobal.gCalc = calcEvent 'Set the object declared in gModule
Set mGlobal.gCalc.Worksheet = ActiveSheet
mGlobal.gCalc.Calc
End Sub
Note that this is using the variable you put in gModule... The event that is actually called is still calcEvent_BeforeCalc(), which is good as this way you can have n number of objects defined in gModule that would all fire off the same event code when the event is triggered.
To simplify the code, you could always just write:
Private Sub Worksheet_Activate()
Set calcEvent = New cCalc
Set calcEvent.Worksheet = ActiveSheet
calcEvent.Calc
End Sub

Calling OnTime method in a Custom Class

I'm trying to use the .OnTime method in a class module, but can't figure out how to call a procedure in the class. All of the .OnTime examples I've seen refer to using the method from a standard code module rather than a custom class. Is there any way of calling a procedure in the class module rather than a standard code module?
#Alex P: Updated to include code. Here is the Class Module:
Option Explicit
Public Sub Test()
MsgBox "Success"
End Sub
Private Sub Class_Initialize()
Application.OnTime EarliestTime:=Now + TimeValue("00:00:03"), _
Procedure:="Test"
End Sub
And the Standard Module:
Option Explicit
Public Sub TestOnTime()
Dim OnTime As CCOnTime
Set OnTime = New CCOnTime
End Sub
I've also tried Procedure:="CClass.Test"
You can do it, but the call-back needs to be bounced back into the object from a Standard Module or a Worksheet Module or Thisworkbook.
Here is an example that pulses a value in a worksheet cell.
The timer is (almost) encapsulated in the cOnTime Class.
A cOnTime Object is instantiated in the host worksheet, whose code module can have a property to set the pulse time as well as the call-back routine.
If you protect the sheet, it will start pulsing and you can stop it by un-protecting the sheet.
If you navigate away from the host sheet, the timer is killed and if you navigate back it re-starts (as long as the sheet is protected).
Class cOnTime
Option Explicit
Const DEFPulseTime = "PulseTime"
Const DEFearliestTime As Long = 5
Const DEFlatestTime As Long = 15
Public WithEvents wb As Workbook
Public ws As Worksheet
Private DoWhen As String
Public mPulseTime As Long
Public mNextTime As Double
Property Let callBackDoWhen(cb As String)
DoWhen = "'" & wb.Name & "'!" & ws.CodeName & "." & cb 'e.g. 'wb Name.xlsm'!Sheet1.kickdog
End Property
Private Function PulseTime() As Long
On Error Resume Next
PulseTime = CallByName(ws, DEFPulseTime, VbGet)
If Err.number <> 0 Then
PulseTime = DEFearliestTime
End If
On Error GoTo 0
End Function
Property Get designMode() As Boolean
designMode = Not ws.ProtectContents
End Property
Public Sub kickDog()
Const myName As String = "kickDog"
Dim psMessage As String
If ws Is ActiveSheet And Not designMode Then
mNextTime = Now + TimeSerial(0, 0, mPulseTime)
On Error Resume Next
Application.OnTime mNextTime, DoWhen
On Error GoTo 0
End If
Exit Sub
End Sub
Public Sub killDog()
If ws Is Nothing Or mNextTime = 0 Then Exit Sub
On Error Resume Next
Application.OnTime mNextTime, DoWhen, , False
On Error GoTo 0
End Sub
Private Sub Class_Initialize()
Dim errorContext As String
On Error GoTo enableAndExit
Set wb = ActiveWorkbook
Set ws = ActiveSheet
On Error GoTo 0
callBackDoWhen = DEFDoWhen
callBackPulseTime = DEFPulseTime
mPulseTime = PulseTime
kickDog
Exit Sub
enableAndExit:
If Err <> 0 Then
If ws Is Nothing Then
errorContext = "ws"
ElseIf wb Is Nothing Then
errorContext = "wb"
End If
End If
End Sub
Private Sub Class_Terminate()
Const myName As String = "Class_Terminate"
On Error Resume Next
killDog
Set ws = Nothing
Set wb = Nothing
Exit Sub
End Sub
Private Sub wb_WindowActivate(ByVal Wn As Window)
wb_Open
End Sub
Private Sub wb_WindowDeactivate(ByVal Wn As Window)
killDog
End Sub
Private Sub wb_BeforeClose(Cancel As Boolean)
killDog
End Sub
Private Sub wb_BeforeSave(ByVal SaveAsUI As Boolean, Cancel As Boolean)
If SaveAsUI Then killDog
End Sub
In Worksheet Module
Option Explicit
Const cPulseTime As Long = 1
Dim mOnTime As cOnTime
Property Get PulseTime() As Long
PulseTime = cPulseTime
End Property
'****************************************
'Timer call-back for cOnTime
Public Sub kickDog()
' Code to execute on timer event
'******************************************
On Error Resume Next
Me.Cells(1, 1) = Not Me.Cells(1, 1)
On Error GoTo 0
'******************************************
Debug.Print "woof!!"
mOnTime.kickDog
End Sub
Private Sub Worksheet_Activate()
Me.Cells(1,1) = False
Set mOnTime = New cOnTime
End Sub
Private Sub Worksheet_Deactivate()
On Error Resume Next
Set mOnTime = Nothing
End Sub
You are asking for magic - VBA is a comprehensive tool but it is not magic.
The reason is that every Class module is simply a template which can be instantiated any number of times in the application code. Excel could not hope to correctly guess which particular instantiation of the Class module is the correct one on which to invoke the method. You are responsible for making this decision and managing the references to the appropriate Class instance.
Ah you say - But there is no private data/references being used by the method I want called. It is a static method. Well the answer to that is that VBA does not support static methods on Class modules, only on Standard modules. Any method that you wish to declare to the environment as being static is declared as being static by being included in a standard module.
So, place your call-back method in a Standard module, and declare a private member that holds a reference to the particular instance of the Class that you wish to handle the event.
One alternative route which isn't specified by others here but, I think, would theoretically work is:
Register VBA object as an active object with a specified GUID
Launch a PowerShell (or binary) daemon to connect to the object with specified GUID and call a specified method on that object every n seconds.
Pros:
Totally encapsulated
Cons:
Launches external process
Method likely has to be public (unless connection points can be abused)
Potentially crash-prone
I haven't implemented such a solution yet but intend to on stdCOM of stdVBA library if everything works out.