Nach dem Windowstate möchte ich nun auch die Spaltenbreiten und Reihenfolge der Spalten beim DataGridView speichern.

   [Imports System.Collections.Specialized] 
   Dim stringCollection As New System.Collections.SpecializedStringCollection()
   For Each column As DataGridViewColumn In Me.DataGridView1.Columns
       stringCollection.Add(String.Format("{0},{1},{2}", _
                      column.DisplayIndex, _
                      column.Width, column.Visible))
   Next
   My.Settings.GridViewSetttings = stringCollection


'Das Wiederherstellen ist genauso einfach.
   If RestorGridviewSettings Then
      Dim cols As StringCollection = My.Settings.GridViewSetttings
      For i As Integer = 0 To cols.Count - 1
         Dim a As String() = cols(i).Split(","c)
         DataGridView1.Columns(i).DisplayIndex = Int16.Parse(a(0))
         DataGridView1.Columns(i).Width = Int16.Parse(a(1))
         DataGridView1.Columns(i).Visible = Boolean.Parse(a(2))
      Next
      RestorGridviewSettings = False
   End If