Solved

VARIABLE IN MANY CLASS IN VB CODE FILE

Posted on 2011-09-21
8
225 Views
Last Modified: 2012-05-12
Hi All,

I add a class to a project.
In that class I add several public class.

The problem when I add some variables to one of the class.

Error      1      Cannot refer to an instance member of a class from within a shared method or shared member initializer without an explicit instance of the class.       

I want all the variables visible to inside all of the class.

Could it be possible ?

What should I do ?

Thank you.
0
Comment
Question by:emi_sastra
  • 4
  • 4
8 Comments
 
LVL 25

Expert Comment

by:Luis Pérez
ID: 36572770
When inside a class you declare something (property, function, sub, field...) as "shared", it means that the shared object is not associated with a specific instance of the class, but it's associated with the class itself. Therefore, you don't need to create a new instance object of the class to access that member, but you can access the member without creating class instance objects.

Let's see an example:
Public Class MyClass
    Public Shared Function SharedHelloWorld() As String
        Return "Hello, world!"
    End Function

    Public Function NotSharedHelloWorld() As String
        Return "Hello, world!"
    End Function
End Class

Later, in your code:
Dim s As String = MyClass.SharedHelloWorld() 'You CAN do this
Dim s2 As String = MyClass.NotSharedHelloWorld() 'You CAN'T do this, it will throw an exception
'To access NotSharedHelloWorld(), you need to do this:
Dim myObject As MyClass = New MyClass
Dim s3 As String = myObject.NotSharedHelloWorld() 'All right

Hope that helps.
0
 
LVL 1

Author Comment

by:emi_sastra
ID: 36572805
'Variables declares
Dim strVarA as string
etc...

Public Class Finance

   Public shared Function A() as string
         strVarA not visible here.
   End Function

End Class

Public Class Inventory

End Class
0
 
LVL 25

Accepted Solution

by:
Luis Pérez earned 500 total points
ID: 36572853
As A() Is a shared function, to access strVarA it must be also shared.

So change
Dim strVarA As String

For
Private Shared strVarA As String

Hope that helps.
0
Independent Software Vendors: We Want Your Opinion

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!

 
LVL 1

Author Comment

by:emi_sastra
ID: 36572886
Hi RolandDeschain,

It works.

Thank you very much for your help.
0
 
LVL 1

Author Comment

by:emi_sastra
ID: 36572945
Hi RolandDeschain,

One problem, the strVarA is not visible at Class Inventory ?

Thank you.
0
 
LVL 25

Expert Comment

by:Luis Pérez
ID: 36573240
It must be perfectly visible.

Look at this:

Public Class Class1
    Private Shared m_Var As String = String.Empty

    Public Class Class2
        Public Shared Property Var As String
            Get
                Return m_Var
            End Get
            Set(value As String)
                m_Var = value
            End Set
        End Property
    End Class

    Public Class Class3
        Public Shared Property Var As String
            Get
                Return m_Var
            End Get
            Set(value As String)
                m_Var = value
            End Set
        End Property
    End Class
End Class

With this code, you can do this without any problem:
Class1.Class2.Var = "new value"
MsgBox(Class1.Class3.Var) 'The MsgBox shows "new value"

Hope that helps.
0
 
LVL 1

Author Comment

by:emi_sastra
ID: 36573376
Yes, it works.

Thank you very much for your help.
0
 
LVL 25

Expert Comment

by:Luis Pérez
ID: 36573471
You're welcome... and we're here to help.

Greetings!
0

Featured Post

Industry Leaders: We Want Your Opinion!

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

Title # Comments Views Activity
write xml in vb.net 2 41
Sql server insert 13 43
VB.Net - Get ColumnNames of SQL Table 4 19
VB.Net - Not Sure if Multi-threading is What I Need 4 39
It’s quite interesting for me as I worked with Excel using vb.net for some time. Here are some topics which I know want to share with others whom this might help. First of all if you are working with Excel then you need to Download the Following …
Creating an analog clock UserControl seems fairly straight forward.  It is, after all, essentially just a circle with several lines in it!  Two common approaches for rendering an analog clock typically involve either manually calculating points with…
In a recent question (https://www.experts-exchange.com/questions/29004105/Run-AutoHotkey-script-directly-from-Notepad.html) here at Experts Exchange, a member asked how to run an AutoHotkey script (.AHK) directly from Notepad++ (aka NPP). This video…

679 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question