Modify the components of the main class through another class - vb.net

Question

We have a school project and I'm trying to break our code into groups. I set my FormBorderStyle to None so I can modify it. But can I use another class to modify the components I have in my main?
An example would be:
Public Class main
Private Sub btn_title_bar_exit_Click(sender As Object, e As EventArgs) Handles btn_title_bar_exit.Click
Me.Close()
End Sub
Private Sub btn_title_bar_minimize_Click(sender As Object, e As EventArgs) Handles btn_title_bar_minimize.Click
Me.WindowState = FormWindowState.Minimized
End Sub
End Class
Public Class user_interface
'Modify components and the form through here
'example: btn_exit.ForeColor = Color.Black
'example: Me.Close()
End Class
Also wondering, this a good way to break code?

Answer 1

If you just want to separate routines (functions/methods/variables declarations...) because you have loads of code filling your class file, just use :
1) the Partial keyword
Public Partial Class MainClass
' MAIN CONTENT
Public Sub New()
Me.InitializeComponents()
' ...
End Sub
' ...
End Class
and in another file :
Public Partial Class MainClass
' USER INTERFACE HANDLERS...
'Modify components and the form through here
'example: btn_exit.ForeColor = Color.Black
'example: Me.Close()
' ...
End Class
So this is the same Class, and other classes may NOT be able to access/modify its members.
2) or either use #Region to split your code and group them :
Public Class MainClass
#Region "Instanciation..."
Public Sub New()
Me.InitializeComponents()
' ...
End Sub
#End Region
#Region "User Interface..."
'Modify components and the form through here
'example: btn_exit.ForeColor = Color.Black
'example: Me.Close()
Public Sub btn1_Click(...)
Public Sub Picture1_MouseMove(...)
#End Region
#Region "Public Properties..."
'...
#End Region
End Class
Then use the plus/minus to unfold/fold that part of the code.
If you really want to edit the members of your MainClass from another class, say, RemoteClass, there are TONs of way doing it, and it depends on what exactly you want to do.
You could make everything Public in your MainClass :
Locate your Form designer file (the one containing the declaration of all the controls of your Form) and change each declaration to Public.
Private pictureBox1 As Picturebox
' becomes
Public pictureBox1 As Picturebox
(Or just click on a control in the IDE, and change its accessibility level to Public)
Then if you can pass a variable pointing to an instance of MainClass in an instance of RemoteClass, then, through RemoteClass, you can access TheMainClassInstance.pictureBox1, and change its size, location, etc. everything.
Then how to create an instance of MainClass in RemoteClass ? It depends on the structure of your application... Without details, guess what.. we'll have to guess..!
Public Class RemoteClass
Private _InstanceOfMainClass As MainClass = Nothing
Public Sub New(ByRef NewInstanceOfMainClass As MainClass)
_InstanceOfMainClass = NewInstanceOfMainClass
' ^^ this is one way doing it.
' ...
End Sub
' ...
Private Sub ChangeBackgroundColor()
_InstanceOfMainClass.picturebox1.BackColor = Color.Black ' and voila !
End Sub
End Class
Then you have a MainClass in your RemoteClass. Don't forget to dispose of _InstanceOfMainClass to avoid Memory Leak (I assume you know how to..)
How many instances of MainClass do you have ?
If it's just one, and you have several RemoteClass classes, then you could consider to make the member of MainClass you want to access as static (shared) members.
Public Class MainClass
Private Shared _MyInstance As MainClass = Nothing
Private Shared Sub InitializeMyInstance()
If _MyInstance Is Nothing Then
_MyInstance = New MainClass(...)
Else
If _MyInstance.IsDisposed Then
' Requires an IDisposable interface
' and handling of Me.Closed event elsewhere...
_MyInstance = Nothing
_MyInstance = New MainClass(...)
End If
End If
End Sub
Public Shared ReadOnly Property MyInstance() As MainClass
Get
InitializeMyInstance()
Return _MyInstance
End Get
End Property
Public Shared ReadOnly Property PictureBox1() As PictureBox
Get
Return MyInstance.pictureBox1
End Get
End Property
' Create as many Properties as required...
End Class
Then in ANY RemoteClass instance, you just call :
MainClass.PictureBox1.Width = 400
MainClass.Close()
MainClass.PictureBox1.Height = 200
But as I said, this works only if you only have a single instance of MainClass.
If you have several MainClass instances and several RemoteClass instances, consider using Unique IDs and a static function/property to access a specific instance.
How to create an ID ?
Public Class MainClass
Private Shared _NextID As Integer = 0
Private _ID As Integer
Public ReadOnly Property ID() As Integer
Get
Return _ID
End Get
End Property
Public Sub New(...)
Me.InitializeComponents()
' ...
_ID = _NextID
_NextID = _NextID + 1
End Sub
' ...
End Class
Then... Create a sorted list containing all the IDs :
Public Class MainClass
Private Shared _IDsList As New SortedList(Of Integer, MainClass)
' then edit your New() method :
Public Sub New(...)
Me.InitializeComponents()
' ...
_ID = _NextID
_NextID = _NextID + 1
_IDList.Add(_ID, Me)
End Sub
' ...
End Class
Then create a static function to get a specific instance of MainClass by its ID.
Public Class MainClass
' ...
Public Shared Function GetInstanceByID(ByVal iID As Integer) As MainClass
If _IDList.ContainsKey(iID) Then
Return _IDList.Item(iID)
Else
Return Nothing
End If
End Function
' ...
' And create the appropriate Dispose() method
' the appropriate Clear() method
' the appropriate FormClosing events handlers
' etc. etc. etc.
End Sub
the thing is, we don't know what's the purpose of your MainClass, and why RemoteClass instances have to modify MainClass members (which members by the way ? controls, variables, add/remove controls ?)