Using The RichTextBox control

[Marvin Scheinbart]

I'm using a richtextbox to display formatted text. The problem is not
the formatted text but getting the richtextbox to display the text
properly. My program prints out messages to the user. I maintain all
user messages in the richtextbox so the user can have a history of
messages. When the richtextbox fills with text messages, all new text
messages get appended to the bottom of the existing text. These new
messages are not visible. I have to use the scroll bars to scroll down
to see the last messages written to the richtextbox.

How do I force the richtextbox to bottom (or top) justify the text
insertion so that all new messages written are always displayed? I want
the older message to scroll off the screen, not the new messages.


Thanks,

Marv

 

[Roger]

You can use the ScrollToCaret() method to force the text box to scroll
to the beginning of the selected text. Set the SelectionStart property
to the length of the text in the control and it should scroll to the
bottom.

Alternatively, you can use Platform Invoke to send a scroll message to
the control directly:

http://weblogs.asp.net/israelio/archive/2004/07/20/188664.aspx

 

[Marcos Stefanakopolus]

I tend to need to do this sort of thing in the context of an event handler
that's passing me text from a worker thread. This is handy for giving your
program a quick-and-dirty "debug console" window:

public void UpdateDebugTextBox(object epitome, StringEventArgs e)
{
if(DebugTextBox.InvokeRequired)
{
this.BeginInvoke(new Epitome.EpitomeStringEvent(UpdateDebugTextBox),
new object[]{epitome, e});
}
else
{
DebugTextBox.AppendText(e.status); // e.status contains the string we
want to put in the richtextbox
DebugTextBox.Focus();
DebugTextBox.SelectionStart = DebugTextBox.TextLength;
DebugTextBox.SelectionLength = 0;
DebugTextBox.ScrollToCaret();
}
}