[vba] Is it possible to declare a public variable in vba and assign a default value?

I want to do this but it won't compile:

Public MyVariable as Integer = 123

What's the best way of achieving this?

It's been quite a while, but this may satisfy you :

Public MyVariable as Integer: MyVariable = 123

It's a bit ugly since you have to retype the variable name, but it's on one line.

This is what I do when I need Initialized Global Constants:
1. Add a module called Globals
2. Add Properties like this into the Globals module:

Property Get PSIStartRow() As Integer  
    PSIStartRow = Sheets("FOB Prices").Range("F1").Value  
End Property  
Property Get PSIStartCell() As String  
    PSIStartCell = "B" & PSIStartRow  
End Property

You can define the variable in General Declarations and then initialise it in the first event that fires in your environment.

Alternatively, you could create yourself a class with the relevant properties and initialise them in the Initialise method

Little-Known Fact:
_{A named range can refer to a value instead of specific cells.}

This could be leveraged to act like a "global variable", plus you can refer to the value from VBA and in a worksheet cell, and the assigned value will even persist after closing & re-opening the workbook!

• To "declare" the name myVariable and assign it a value of 123:

  ThisWorkbook.Names.Add "myVariable", 123
  

• To retrieve the value (for example to display the value in a MsgBox):

    MsgBox [myVariable]
  

• Alternatively, you could refer to the name with a string: (identical result as square brackets)

  MsgBox Evaluate("myVariable")
  

• To use the value on a worksheet just use it's name in your formula as-is:

  =myVariable
  

• In fact, you could even store function expressions: (sort of like in JavaScript)
  ^{(Admittedly, I can't actually think of a situation where this would be beneficial - but I don't use them in JS either.)}

  ThisWorkbook.Names.Add "myDay", "=if(isodd(day(today())),""on day"",""off day"")"
  

Square brackets are just a shortcut for the Evaluate method. I've heard that using them is considered messy or "hacky", but I've had no issues and their use in Excel is supported by Microsoft.

There is probably also a way use the Range function to refer to these names, but I don't see any advantage so I didn't look very deeply into it.

More info:

• Microsoft Office Dev Center: Names.Add method (Excel)
• Microsoft Office Dev Center: Application.Evaluate method (Excel)

Sure you know, but if its a constant then const MyVariable as Integer = 123 otherwise your out of luck; the variable must be assigned an initial value elsewhere.

You could:

public property get myIntegerThing() as integer
    myIntegerThing= 123
end property

In a Class module then globally create it;

public cMyStuff as new MyStuffClass

So cMyStuff.myIntegerThing is available immediately.

As told above, To declare global accessible variables you can do it outside functions preceded with the public keyword.

And, since the affectation is NOT PERMITTED outside the procedures, you can, for example, create a sub called InitGlobals that initializes your public variables, then you just call this subroutine at the beginning of your statements

Here is an example of it:

Public Coordinates(3) as Double
Public Heat as double
Public Weight as double

Sub InitGlobals()
    Coordinates(1)=10.5
    Coordinates(2)=22.54
    Coordinates(3)=-100.5
    Heat=25.5
    Weight=70
End Sub

Sub MyWorkSGoesHere()
    Call InitGlobals
    'Now you can do your work using your global variables initialized as you wanted them to be.
End Sub

Just to offer you a different angle -

I find it's not a good idea to maintain public variables between function calls. Any variables you need to use should be stored in Subs and Functions and passed as parameters. Once the code is done running, you shouldn't expect the VBA Project to maintain the values of any variables.

The reason for this is that there is just a huge slew of things that can inadvertently reset the VBA Project while using the workbook. When this happens, any public variables get reset to 0.

If you need a value to be stored outside of your subs and functions, I highly recommend using a hidden worksheet with named ranges for any information that needs to persist.