Most other solutions on the web for this problem say to use the ScrolLToCarret() method. This method had two problems for me:

1) The scrollbar of the RichTextBox would flicker (jump up and then down) whenever I called ScrolLToCarret().

2) The RichTextBox would never scroll *all the way* down. It would always stop a few pixels above the bottom (so annoying!).

Your solution solves both of these problems and makes my work look a bit more professional . Kudos to you and many thanks.

- Harvo

Also the usage method should be:

private void anyTextBox_TextChanged(object sender, EventArgs e)
{
anyTextBox.ScrollToBottom();
}

[code]
using System;
using System.Runtime.InteropServices;

namespace Extensions
{
public static class UIExtensions
{
[DllImport("user32.dll", CharSet = CharSet.Auto)]
private static extern IntPtr SendMessage(
IntPtr hWnd,
uint Msg,
IntPtr wParam,
IntPtr lParam);

private const int WM_VSCROLL = 277;
private const int SB_LINEUP = 0;
private const int SB_LINEDOWN = 1;
private const int SB_TOP = 6;
private const int SB_BOTTOM = 7;

public static void ScrollToBottom(this System.Windows.Forms.TextBoxBase tb)
{
SendMessage(tb.Handle, WM_VSCROLL, new IntPtr(SB_BOTTOM), new IntPtr(0));
}

public static void ScrollToTop(this System.Windows.Forms.TextBoxBase tb)
{
SendMessage(tb.Handle, WM_VSCROLL, new IntPtr(SB_TOP), new IntPtr(0));
}

public static void ScrollLineDown(this System.Windows.Forms.TextBoxBase tb)
{
SendMessage(tb.Handle, WM_VSCROLL, new IntPtr(SB_LINEDOWN), new IntPtr(0));
}

public static void ScrollLineUp(this System.Windows.Forms.TextBoxBase tb)
{
SendMessage(tb.Handle, WM_VSCROLL, new IntPtr(SB_LINEUP), new IntPtr(0));
}

}
}
[/code]

Usage is exactly the same:

[code]
private void anyTextBox_TextChanged(object sender, EventArgs e)
{
textLogMain.ScrollToBottom();
}
[/code]