How to reference a class variable from another class in vb.net

Question

I have the following (simplified to make this easy to read)

first class:

Class MainWindow
     Private mFile As myFile 'myFile is a class containing a bunch of stuff

     Sub go()
          dim editFiles as New EditFiles(mFile)
     End Sub
End Class

Second Class:

Public Class EditFiles
    Private mFile As myFile 'myFile is a class containing a bunch of stuff
Sub New(ByRef passedFile As myFile)

    ' This call is required by the designer.
    InitializeComponent()

    ' Add any initialization after the InitializeComponent() call.

    mFile = passedFile

End Sub

what I would like to happen is any changes I make to mFile in the second class to also change mFile in the first class, I thought that by passing it ByRef in the initialization that would happen but apparently not.

What I am wondering is what is the appropriate method to make this work? I know I could create a global variable but there must be a way to pass the pointer of mFile from the first class so that mFile in the second class is essentially the same.

If you could show me a simple example perhaps by editing the above code I would really appreciated it!

Answer 1

Here is how I ended up solving my problem:

 Class MainWindow
 Private  mFile As myFile 'myFile is a class containing a bunch of stuff

 Sub go()
      dim editFiles as New EditFiles(me, mFile)
 End Sub

 sub setMFile(_mfile as myfile)
    me.mfile = _mfile
 End Class

Second class

Public Class EditFiles
Private mainWindow As mainWindow
Private mFile as myFile
Sub New(ByVal sourceWindow As mainWindow, byVal sourceFile as myFile)

     ' This call is required by the designer.
    InitializeComponent()

    ' Add any initialization after the InitializeComponent() call.
    mainWindow = sourceWindow
    mFile = sourceFile

end Sub
Sub setFile
    mainWindow.setMFile(mFile)
End Sub

Answer 2

You should create an object of the first class in the second class. Also you need a method that changes the value of mFile in the first class. It should be something like the following.

Class MainWindow
     Private  mFile As myFile 'myFile is a class containing a bunch of stuff

     Sub go()
          dim editFiles as New EditFiles(mFile)

     End Sub

     sub setMFile(_mfile as myfile)
        me.mfile = _mfile
End Class

Second class

Public Class EditFiles
    Private mFile As myFile 'myFile is a class containing a bunch of stuff
    Sub New(ByRef passedFile As myFile)

    ' This call is required by the designer.
    InitializeComponent()

    ' Add any initialization after the InitializeComponent() call.

    mFile = passedFile
    dim newObject as new MainWindow
    newobject.setMFile(mFile)
End Sub

Answer 3

You need to make sure MainWindow's mFile variable is initialized before passing it to the EditFiles object.

Also, if myFile is a Class, you don't even need to pass it ByRef.