How do I declare a global variable in VBA? - excel

Question

I wrote the following code:
Function find_results_idle()
Public iRaw As Integer
Public iColumn As Integer
iRaw = 1
iColumn = 1
And I get the error message:
"invalid attribute in Sub or Function"
Do you know what I did wrong?
I tried to use Global instead of Public, but got the same problem.
I tried to declare the function itself as `Public, but that also did no good.
What do I need to do to create the global variable?

Answer 1

You need to declare the variables outside the function:
Public iRaw As Integer
Public iColumn As Integer
Function find_results_idle()
iRaw = 1
iColumn = 1

Answer 2

This is a question about scope.
If you only want the variables to last the lifetime of the function, use Dim (short for Dimension) inside the function or sub to declare the variables:
Function AddSomeNumbers() As Integer
Dim intA As Integer
Dim intB As Integer
intA = 2
intB = 3
AddSomeNumbers = intA + intB
End Function
'intA and intB are no longer available since the function ended
A global variable (as SLaks pointed out) is declared outside of the function using the Public keyword. This variable will be available during the life of your running application. In the case of Excel, this means the variables will be available as long as that particular Excel workbook is open.
Public intA As Integer
Private intB As Integer
Function AddSomeNumbers() As Integer
intA = 2
intB = 3
AddSomeNumbers = intA + intB
End Function
'intA and intB are still both available. However, because intA is public, '
'it can also be referenced from code in other modules. Because intB is private,'
'it will be hidden from other modules.
You can also have variables that are only accessible within a particular module (or class) by declaring them with the Private keyword.
If you're building a big application and feel a need to use global variables, I would recommend creating a separate module just for your global variables. This should help you keep track of them in one place.

Answer 3

To use global variables, Insert New Module from VBA Project UI and declare variables using Global
Global iRaw As Integer
Global iColumn As Integer

Answer 4

The question is really about scope, as the other guy put it.
In short, consider this "module":
Public Var1 As variant 'Var1 can be used in all
'modules, class modules and userforms of
'thisworkbook and will preserve any values
'assigned to it until either the workbook
'is closed or the project is reset.
Dim Var2 As Variant 'Var2 and Var3 can be used anywhere on the
Private Var3 As Variant ''current module and will preserve any values
''they're assigned until either the workbook
''is closed or the project is reset.
Sub MySub() 'Var4 can only be used within the procedure MySub
Dim Var4 as Variant ''and will only store values until the procedure
End Sub ''ends.
Sub MyOtherSub() 'You can even declare another Var4 within a
Dim Var4 as Variant ''different procedure without generating an
End Sub ''error (only possible confusion).
You can check out this MSDN reference for more on variable declaration and this other Stack Overflow Question for more on how variables go out of scope.
Two other quick things:
Be organized when using workbook level variables, so your code doesn't get confusing. Prefer Functions (with proper data types) or passing arguments ByRef.
If you want a variable to preserve its value between calls, you can use the Static statement.

Answer 5

If this function is in a module/class, you could just write them outside of the function, so it has Global Scope. Global Scope means the variable can be accessed by another function in the same module/class (if you use dim as declaration statement, use public if you want the variables can be accessed by all function in all modules) :
Dim iRaw As Integer
Dim iColumn As Integer
Function find_results_idle()
iRaw = 1
iColumn = 1
End Function
Function this_can_access_global()
iRaw = 2
iColumn = 2
End Function

Answer 6

Also you can use -
Private Const SrlNumber As Integer = 910
Private Sub Workbook_Open()
If SrlNumber > 900 Then
MsgBox "This serial number is valid"
Else
MsgBox "This serial number is not valid"
End If
End Sub
Its tested on office 2010

Answer 7

The best way I find is to assign a property to the Workbook
It's scope remains valid as long as the workbook is open
Public WhenOpened As Date
Private Sub Workbook_Open()
ThisWorkbook.WhenOpened = Now()
End Sub

Answer 8

Create a public integer in the General Declaration.
Then in your function you can increase its value each time.
See example (function to save attachements of an email as CSV).
Public Numerator As Integer
Public Sub saveAttachtoDisk(itm As Outlook.MailItem)
Dim objAtt As Outlook.Attachment
Dim saveFolder As String
Dim FileName As String
saveFolder = "c:\temp\"
For Each objAtt In itm.Attachments
FileName = objAtt.DisplayName & "_" & Numerator & "_" & Format(Now, "yyyy-mm-dd H-mm-ss") & ".CSV"
objAtt.SaveAsFile saveFolder & "\" & FileName
Numerator = Numerator + 1
Set objAtt = Nothing
Next
End Sub

Answer 9

A good way to create Public/Global variables is to treat the Form like a class object and declare properties and use Public Property Get [variable] to access property/method. Also you might need to reference or pass a Reference to the instantiated Form module. You will get errors if you call methods to forms/reports that are closed.
Example: pass Me.Form.Module.Parent into sub/function not inside form.
Option Compare Database
Option Explicit
''***********************************''
' Name: Date: Created Date Author: Name
' Current Version: 1.0
' Called by:
''***********************************''
' Notes: Explain Who what when why...
' This code Example requires properties to be filled in
''***********************************''
' Global Variables
Public GlobalData As Variant
''***********************************''
' Private Variables
Private ObjectReference As Object
Private ExampleVariable As Variant
Private ExampleData As Variant
''***********************************''
' Public properties
Public Property Get ObjectVariable() As Object
Set ObjectVariable = ObjectReference
End Property
Public Property Get Variable1() As Variant
'Recommend using variants to avoid data errors
Variable1 = ExampleVariable
End property
''***********************************''
' Public Functions that return values
Public Function DataReturn (Input As Variant) As Variant
DataReturn = ExampleData + Input
End Function
''***********************************''
' Public Sub Routines
Public Sub GlobalMethod()
'call local Functions/Subs outside of form
Me.Form.Refresh
End Sub
''***********************************''
' Private Functions/Subs used not visible outside
''***********************************''
End Code
So in the other module you would be able to access:
Public Sub Method1(objForm as Object)
'read/write data value
objForm.GlobalData
'Get object reference (need to add Public Property Set to change reference object)
objForm.ObjectVariable
'read only (needs Public property Let to change value)
objForm.Variable1
'Gets result of function with input
objForm.DataReturn([Input])
'runs sub/function from outside of normal scope
objForm.GlobalMethod
End Sub
If you use Late Binding like I do always check for Null values and objects that are Nothing before attempting to do any processing.