Disabling RichTextBox autoscroll

Question

I am using RichTextBox control for displaying application logs. I am updating control once a second with a few calls of RichTextBox::AppendText method. What is really annoyi

Answer 1

If your issue is with the "Vertical Scroll" scrolling down when you are adding the Log text, but you would want it to be on top all the time:

you have to add event handlers to VScroll, TextChanged events and in the event handler set the scroll to top

richTextBox1.VScroll += HandleRichTextBoxAdjustScroll;
richTextBox1.TextChanged += HandleRichTextBoxAdjustScroll;

private const UInt32 SB_TOP = 0x6;
private const UInt32 WM_VSCROLL = 0x115;

[return: MarshalAs(UnmanagedType.Bool)]
[DllImport("user32.dll", SetLastError = true)]
private static extern bool PostMessage(IntPtr hWnd, UInt32 Msg,
    IntPtr wParam, IntPtr lParam);

private void HandleRichTextBoxAdjustScroll(Object sender,
    EventArgs e)
{
    PostMessage(handle, WM_VSCROLL, (IntPtr)SB_TOP, IntPtr.Zero);
}

You could do the same with horizontal scroll bar too. Replace WM_VSCROLL with WM_HSCROLL and SB_TOP with SB_LEFT

private const UInt32 WM_HSCROLL = 0x0114;
private const UInt32 SB_LEFT = 0x06;