C#: Synchronize Scroll Position of two RichTextBoxes?

Question

In my application\'s form, I have two RichTextBox objects. They will both always have the same number of lines of text. I would like to \"synchronize\" the vert

Answer 1

const int WM_USER = 0x400;

const int EM_GETSCROLLPOS = WM_USER + 221;

const int EM_SETSCROLLPOS = WM_USER + 222;

[System.Runtime.InteropServices.DllImport("user32.dll")]
static extern int SendMessage(IntPtr hWnd, int msg, int wParam, ref Point lParam);

private void RichTextBox1_VScroll(object sender, EventArgs e)
{
    Point pt;

    SendMessage(RichTextBox1.Handle, EM_GETSCROLLPOS, 0, ref pt);

    SendMessage(RichTextBox2.Handle, EM_SETSCROLLPOS, 0, ref pt);
}


private void RichTextBox2_VScroll(object sender, EventArgs e)
{
    Point pt;

    SendMessage(RichTextBox1.Handle, EM_GETSCROLLPOS, 0, ref pt);

    SendMessage(RichTextBox2.Handle, EM_SETSCROLLPOS, 0, ref pt);
}