Universal Variable

Can I create a variable in VB that I can access in any form or module? I just want to know if that's possible and how to do it. I don't want any alternatives. Thank you

I know one way is to declare a Global variable outside of a function or a sub.
I think this can only be done inside a module, but I could be wrong on this

Code:

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Global MyVar as String

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This will then work across the entire project.

EDIT - Make sure that you declare this at the very beginning of a module, ie, before you have begun a Sub or Function.

I think it's usual to use the Public keyword nowadays rather than the Global keyword.
You can use a Public variable in a form but you have to specify the form name when you wish to reference it outside of the form... Form1.MyPublicString. I believe this is not recommended because a Form unlike a Module is effectively a Class which can be unloaded and dereferenced.

Quote:

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Originally Posted by Milk

You can use a Public variable in a form but you have to specify the form name when you wish to reference it outside of the form... Form1.MyPublicString. I believe this is not recommended because a Form unlike a Module is effectively a Class which can be unloaded and dereferenced.

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When talking about a public variable inside a form, you're really talking about adding a public property to a form:

vb Code:

Option Explicit
 
Private mstrTest As String
 
Private Sub Form_Load()
    mstrTest = "Hello, World!"
End Sub
 
Public Property Let Test(pstrTest As String)
    mstrTest = pstrTest
End Sub
 
Public Property Get Test() As String
    Test = mstrTest
End Sub

Debug.Print Form1.Test

Creating as a property is a better idea, as it will be a property anyway. So by declaring Public Test As String you're actually doing the same Ellis Dee posted above, just with a shorter syntax, but if you want to have any handling you have to do the long syntax anyway.

As for creating public properties such as that one, they're useful in some cases even in forms. Say you have made a form of which there can be multiple copies running, but you want to control certain aspect individually, such as you've added a gradient background feature and thus want to add properties BackColor2 (OLE_COLOR) and Gradient (Boolean) to have control over the new feature.

However, keeping public information such as program settings is better to do in a module or centralize it into it's own class module. This goes as far as into the application design: forms as visual and interactive elements should be dedicated for that, and shoudn't be used as the main storage of the information.

On top of any module (that is not form or class), declare:

Code:

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Public myUniversalVariable As AnyType

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Public has replaced Global
Private has replaced Dim

All work but Public and Private are now perfered over Global and Dim

Quote:

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Originally Posted by jmsrickland

Public has replaced Global
Private has replaced Dim

All work but Public and Private are now perfered over Global and Dim

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Public has replaced Global: OK!
Private has replaced Dim: Not quite right!

You cannot replace

Code:

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Sub ABC()
  Dim x As Long
  ...
End Sub

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with

Code:

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Sub ABC()
  Private x As Long
  ...
End Sub

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Private can only be used instead of Dim at Module level.

Well, that's what we were talking about; a universal variable as the OP put it.

Okay, thank you! So, what's the difference between using "Global" or "Public" in a module? Also, I was wondering, is "Dim" short for something?

Along with "Public has replaced Global", the statement "Private has replaced Dim" is misleading.

"Public" is the new keyword for "Global" (both can be used interchangeable), they can be used to declare a variable on top of a module or a procedure (Sub/Function), these variable and procedure can be accessed anywhere in the project (unless there is other restriction).

"Private" and "Dim" can be used interchangeable at Module level only, and "Private has not replaced Dim".
"Private" is also can be used to declare a procedure that will be available within the module only.

"Dim" is short for "Dimension"

"Dim" is "Dim", it means dimension but it is not the short form of "Dimension", ie. "Dimension" cannot be used in places of "Dim".