Smooth scrolling rich text box with timer

Hey,

I'm wondering how to scroll smoothly down a RTB using a timer. By smooth im not meaning one line at a time, but more a few pixels.

How do I do this?

Thanks,
Jessee

resize your rtb so it shows all of the text, set scrollbars = none, then paste it onto a panel. set the panel autoscroll property to true, then:

vb Code:

''' <summary>
''' timer
''' </summary>
''' <param name="sender"></param>
''' <param name="e"></param>
''' <remarks>interval = 100ms</remarks>
Private Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer1.Tick
    Panel1.AutoScrollPosition = New Point(Panel1.AutoScrollPosition.X, Math.Abs(Panel1.AutoScrollPosition.Y) + 1)
End Sub

Hey,

That works but since the text in the rich text box changes length, I cant have a fixed size textbox.

Which means I have a huge textbox, and the scroll bar on the panel is huge.

Is there an easier way?

Thanks!
Jessee

ok here's an alternative method without the panel. it uses the windows API function sendmessage:

vb Code:

Public Class Form1
 
    Declare Function SendMessage Lib "user32.dll" Alias "SendMessageA" (ByVal hWnd As IntPtr, ByVal msg As Integer, ByVal wParam As Integer, ByRef lParam As POINT) As Integer
 
    Const EM_GETSCROLLPOS As Integer = 1245
    Const EM_SETSCROLLPOS As Integer = 1246
 
    Structure POINT
        Dim x As Integer
        Dim y As Integer
    End Structure
 
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        Timer1.Enabled = True
    End Sub
 
    Private Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer1.Tick
        Dim p As New POINT
        SendMessage(RichTextBox1.Handle, EM_GETSCROLLPOS, 0, p)
        p.y += 1
        SendMessage(RichTextBox1.Handle, EM_SETSCROLLPOS, 0, p)
    End Sub
 
End Class