Powershell: Sync Scrolling of two Richtextboxes

Question

I want to sync the scrolling of two Winforms Richtextboxes. When RTB2 gets scolled, RTB1 needs to be exactly aligned all the time. I tried to convert this c#-Code here LINK (second answer), but failed so far. So I need help. Right now it produces multiple errors:

Type [ScrollBarCommands] was not found...
Type [ScrollBarType] was not found....
Type [Message] was not found...
Also "illegal conversions" and so on.

This is an example script:

[void][System.Reflection.Assembly]::LoadWithPartialName("System.Windows.Forms")
$form = New-Object system.Windows.Forms.Form
$form.size  = "400,400"
$rtb1 = New-Object system.Windows.Forms.RichTextBox
$rtb1.size  = "190,350"
$rtb1.location = "200,1"
$rtb1.text = (1..300 | out-string)
$form.controls.add($rtb1)
$rtb2 = New-Object system.Windows.Forms.RichTextBox
$rtb2.size  = "190,350"
$rtb2.location = "1,1"
$rtb2.text = (1..300 | out-string)
$rtb2.scrollbars = "none"
$form.controls.add($rtb2)

$code = @'
public enum ScrollBarType : uint {
   SbHorz = 0,
   SbVert = 1,
   SbCtl = 2,
   SbBoth = 3
 }
public enum Message : uint {
   WM_VSCROLL = 0x0115
}
public enum ScrollBarCommands : uint {
   SB_THUMBPOSITION = 4
}
[DllImport( "User32.dll" )]
public extern static int GetScrollPos( IntPtr hWnd, int nBar );
[DllImport( "User32.dll" )]
public extern static int SendMessage( IntPtr hWnd, uint msg, IntPtr wParam, IntPtr lParam );
'@
Add-Type -Name WinUtils -MemberDefinition $code -Namespace User32

$rtb1.add_VScroll({ 
   [uint32]$nPos = [User32.WinUtils]::GetScrollPos( $rtb1.Handle, [ScrollBarType]::SbVert )
   [uint32]$npos = $nPos -shl 16
   [uint32]$wParam = [ScrollBarCommands]::SB_THUMBPOSITION -bor $nPos
   [User32.WinUtils]::SendMessage( $rtb2.Handle, [Message]::WM_VSCROLL, $wParam , [ref]0)
})

$form.showdialog()

Editors, please note: It's not a duplicate, this is about **Powershell. :)**

Answer 1

ScrollBarType, ScrollBarCommands, and Message are members of User32.WinUtils namespace. Also, ptr should be System.IntPtr.

EDIT: To scroll $rtb2 while dragging the scrollbar (and not just when mouse is released), you have to use GetScrollInfo

EDIT 2: Fixed arrow scroll buttons not working

EDIT 3: Fixed other bugs. Restructured code.

$typeDef = @"
using System;
using System.Windows.Forms;
using System.Runtime.InteropServices;

public enum ScrollBarType : uint {
    SbHorz = 0,
    SbVert = 1,
    SbCtl  = 2,
    SbBoth = 3
}

public enum Message : uint {
    WmVScroll = 0x0115
}

public enum ScrollBarCommands : uint {
    ThumbPosition = 4,
    ThumbTrack    = 5
}

[Flags()]
public enum ScrollBarInfo : uint {
    Range           = 0x0001,
    Page            = 0x0002,
    Pos             = 0x0004,
    DisableNoScroll = 0x0008,
    TrackPos        = 0x0010,

    All = ( Range | Page | Pos | TrackPos )
}

public class CustomRichTextBox : RichTextBox {
    public Control Buddy { get; set; }

    public bool ThumbTrack = false;

    [StructLayout( LayoutKind.Sequential )]
    public struct ScrollInfo {
        public uint cbSize;
        public uint fMask;
        public int nMin;
        public int nMax;
        public uint nPage;
        public int nPos;
        public int nTrackPos;
    };

    [DllImport( "User32.dll" )]
    public extern static int SendMessage( IntPtr hWnd, uint msg, IntPtr wParam, IntPtr lParam );
    [DllImport( "User32.dll" )]
    public extern static int GetScrollInfo( IntPtr hWnd, int fnBar, ref ScrollInfo lpsi );

    public void CustomVScroll() {
        int nPos;

        ScrollInfo scrollInfo = new ScrollInfo();
        scrollInfo.cbSize = (uint)Marshal.SizeOf( scrollInfo );

        if (ThumbTrack) {
            scrollInfo.fMask = (uint)ScrollBarInfo.TrackPos;
            GetScrollInfo( this.Handle, (int)ScrollBarType.SbVert, ref scrollInfo );
            nPos = scrollInfo.nTrackPos;
        } else {
            scrollInfo.fMask = (uint)ScrollBarInfo.Pos;
            GetScrollInfo( this.Handle, (int)ScrollBarType.SbVert, ref scrollInfo );
            nPos = scrollInfo.nPos;
        }

        nPos <<= 16;
        uint wParam = (uint)ScrollBarCommands.ThumbPosition | (uint)nPos;
        SendMessage( Buddy.Handle, (int)Message.WmVScroll, new IntPtr( wParam ), new IntPtr( 0 ) );
    }

    protected override void WndProc( ref System.Windows.Forms.Message m ) {
        if ( m.Msg == (int)Message.WmVScroll ) {
            if ( ( m.WParam.ToInt32() & 0xFF ) == (int)ScrollBarCommands.ThumbTrack ) {
                ThumbTrack = true;
            } else {
                ThumbTrack = false;
            }
        }

        base.WndProc( ref m );
    }
}
"@

$assemblies = ("System.Windows.Forms", "System.Runtime.InteropServices")

Add-Type -ReferencedAssemblies $assemblies -TypeDefinition $typeDef -Language CSharp

### Form

$form = New-Object System.Windows.Forms.Form
$form.Size = "400,400"

### Rich text box 1 (Synchronized - master)

$rtb1 = New-Object CustomRichTextBox

$rtb1.Size = "190,350"
$rtb1.Location = "200,1"
$rtb1.Text = (1..300 | Out-String)

$form.Controls.Add($rtb1)

### Rich text box 2 (Synchronized - slave)

$rtb2 = New-Object system.Windows.Forms.RichTextBox

$rtb2.Size = "190,350"
$rtb2.Location = "1,1"
$rtb2.Text = (1..300 | Out-String)
$rtb2.ScrollBars = "none"

$form.Controls.Add($rtb2)

### Synchronization setup

$rtb1.Buddy = $rtb2

$rtb1.Add_VScroll({
    $this.CustomVScroll()
})

### Run

$form.ShowDialog()