Refreshing a datagrid on another form

[BukHix]

I am trying to refresh a datagrid on one form from another. I found a code sample on this forum where I could click a button from a second form like this (Public Shared):

Form1

' This is form1 
    Public Shared Sub Button1_Click _
        (ByVal sender As System.Object, _
        ByVal e As System.EventArgs) Handles Button1.Click
 
        MsgBox("Hello World")
 
    End Sub
 
    Private Sub Button2_Click _
        (ByVal sender As System.Object, _
        ByVal e As System.EventArgs) Handles Button2.Click
 
        Dim xForm As New Form2
        xForm.Show()
 
    End Sub

Form2

Private Sub Button1_Click _
        (ByVal sender As System.Object, _
        ByVal e As System.EventArgs) Handles Button1.Click
 
        Dim zForm As New Form1
        zForm.Button1_Click(Me, Nothing)
 
    End Sub

Pushing the button on the second form causes the button on the first form to show the Hello World message.

Now when I try to do the same thing with a button that refresshes a datagrid I get this error: 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.

How do I overcome that?