[RESOLVED] Infinite undo/redo: how do you implement it?

[bergerkiller]

<post cleared, time for final result>

Got it all working very nicely, but it took some workaround:

Public Class ScrollData
        Sub New(ByVal control As Control, ByVal scroll As Bar, Optional ByVal flags As Mask = Mask.ALL)
            Me.SetData(control.Handle, scroll, flags)
        End Sub
        Sub New(ByVal handle As IntPtr, ByVal scroll As Bar, Optional ByVal flags As Mask = Mask.ALL)
            Me.SetData(handle, scroll, flags)
        End Sub
        Public Sub SetData(ByVal handle As IntPtr, ByVal scroll As Bar, Optional ByVal flags As Mask = Mask.ALL)
            Me.flags = flags
            Dim s As New SCROLLINFO(Me.flags)
            SCROLLINFO.GetScrollInfo(handle, scroll, s)
            Me.handle = handle
            Me.scroll = scroll
            Me.Minimum = s.nMin
            Me.Maximum = s.nMax
            Me.Position = s.nPos
            Me.Page = s.nPage
            Me.TrackPosition = s.nTrackPos
        End Sub
        Public flags As mask
        Public handle As IntPtr
        Public scroll As Bar
        Public Minimum As Integer
        Public Maximum As Integer
        Public Page As UInteger
        Public Position As Integer
        Public TrackPosition As Integer
        Public Function Update(Optional ByVal redraw As Boolean = True) As Integer
            Dim s As New SCROLLINFO(Me.flags)
            s.nMin = Me.Minimum
            s.nMax = Me.Maximum
            s.nPos = Me.Position
            s.nPage = Me.Page
            s.nTrackPos = Me.TrackPosition
            Return SCROLLINFO.SetScrollInfo(Me.handle, Me.scroll, s, redraw)
        End Function
        Public Enum Bar As Integer
            Horizontal = 0
            Vertical = 1
            Client = 2
            Both = 3
        End Enum
        Public Enum Mask As UInteger
            Range = &H1
            Page = &H2
            Position = &H4
            DisableNoScroll = &H8
            TrackPosition = &H10
            ALL = Range Or Page Or Position Or TrackPosition
        End Enum
        Private Structure SCROLLINFO
            Public Declare Function GetScrollInfo Lib "user32" (ByVal hWnd As IntPtr, ByVal fnBar As Bar, ByRef lpScrollInfo As SCROLLINFO) As Boolean
            Public Declare Function SetScrollInfo Lib "user32" (ByVal hWnd As IntPtr, ByVal fnBar As Bar, ByRef lpScrollInfo As SCROLLINFO, ByVal redraw As Boolean) As Integer
            Sub New(ByVal mask As Mask)
                Me.cbSize = Marshal.SizeOf(Me)
                Me.fMask = mask
            End Sub
            Private cbSize As UInteger
            Private fMask As Mask
            Public nMin As Integer
            Public nMax As Integer
            Public nPage As UInteger
            Public nPos As Integer
            Public nTrackPos As Integer
        End Structure
    End Class

Usage:

        Dim s As New ScrollData(TextBox1, ScrollData.Bar.Vertical)
        s.Position += 1
        s.Update()

Added the API structure inside a class so I was able to hold the scroll type loaded and the Handle of it, since passing the arguments all the time is a bit useless.

Thanks all, especially Paul for reviving the ScrollInfo idea and for the previous examples.