《控件按比例随窗体缩放》的代码报错 System.Windows.Forms.Control.Tag.get 返回 Nothing

Public Class Form1

Dim x As Single = 0
Dim y As Single = 0
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
'得到原始窗体大小
x = Me.Width
y = Me.Height
setTag(Me)
End Sub

Private Sub Form1_Resize(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Resize
'得到现在窗体的大小，然后根据原始大小计算缩放比例
Dim newx As Single = Me.Width / x
Dim newy As Single = Me.Height / y
setControls(newx, newy, Me)
End Sub
'递归取控件的原始大小和位置，用tag来纪录
Private Sub setTag(ByVal obj As Object)
For Each con As Control In obj.Controls
con.Tag = con.Width & ":" & con.Height & ":" & con.Left & ":" & con.Top & ":" & con.Font.Size
'如果是容器控件，则递归继续纪录
If con.Controls.Count > 0 Then
setTag(con)
End If
Next
End Sub
'递归重新设定控件的大小和位置
Private Sub setControls(ByVal newx As Single, ByVal newy As Single, ByVal obj As Object)
For Each con As Control In obj.Controls
con.AutoSize = False
Dim mytag() As String = con.Tag.ToString.Split(":")
con.Width = mytag(0) * newx
con.Height = mytag(1) * newy
con.Left = mytag(2) * newx
con.Top = mytag(3) * newy
'计算字体缩放比例，缩放字体
Dim currentSize As Single = newy * mytag(4)
con.Font = New Font(con.Font.Name, currentSize, _
con.Font.Style, con.Font.Unit)
'如果是容器控件，则递归继续缩放
If con.Controls.Count > 0 Then
setControls(newx, newy, con)
End If
Next
End Sub
End Class

这段代码是我在网上复制的《控件按比例随窗体缩放》的代码，我在一个窗口中已经调试成功了，然而在另一个窗体中的出现《System.NullReferenceException:“未将对象引用设置到对象的实例。”System.Windows.Forms.Control.Tag.get 返回 Nothing。》的错误，然后我从新建立了一个窗体应用，随意加几个控件也是这个错误，我再次将通过调试的窗体控件复制到新建的窗体应用里面，再次调试，还是这个错误，请问我这问题到底可能出在哪里呢，请帮忙，谢谢
收起
我X，我刚刚随意更改那个调试成功窗体里面的一个控件的位置，然后调试就不成功了........