Access main form control from inside created class

Hi, I have a form MainWindow and it populates a tab control with instances of mytab class.

mytab has a datagrid and when selections are made I need to change the contents of a label on the main form (lblInfo).

I have no problem getting the data to a variable but I can't find a way to access the labels properties to display my info from inside the code for mytab class.

How can I access this labels properties from the new class?

in vb6 I think it would have worked to write MainWindow.lblInfo = "whatever" but that doesn't work.

I tried initiating the main form as

public mainwin = new MainWindow

mainwin.show

then in the class go for mainwin.lblInfo

but this says mainwin is not declared. it may be inaccessible due to its protection level.

I feel like there is a concept I'm missing here. Any help appreciated. Thanks.

I'm not sure what are you asking, but may be this will help you.
Why are you not try to create new property in your class with data type label, say the code like this:

Put this code in a class or add new class
=============================
Public Class Class1
    Private mLabelInfo As Label

    Public Property LabelInfo() As Label
        Get
            LabelInfo = mLabelInfo
        End Get
        Set(ByVal value As Label)
            mLabelInfo = value
        End Set
    End Property
End Class

Put the code in a Form and add button named button1
=======================================
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        Dim c1 As New Class1
        c1.LabelInfo = Label1
        c1.LabelInfo.Text = "Text Changed!"
    End Sub

Try that and let me know the result