> Hello, I've RichTextBox with quite long text (thousands of lines) and I'm
> doing something line syntax coloring. I set different colors to each word,
> number etc. with selecting the text (Select()) and the setting
> SelectionColor. But it's very slow. I even tried to send the messages
> manually and avoid the calling of SelectionColor (that's the slowest thing)
> but it's not much better. How to do this effectively?

"AMercer" wrote:

> > Hello, I've RichTextBox with quite long text (thousands of lines) and I'm
> > doing something line syntax coloring. I set different colors to each word,
> > number etc. with selecting the text (Select()) and the setting
> > SelectionColor. But it's very slow. I even tried to send the messages
> > manually and avoid the calling of SelectionColor (that's the slowest thing)
> > but it's not much better. How to do this effectively?
>
> I don't think there is a way to get good performance with the RichTextBox
> methods. I think the reason is that every highlight operation you do results
> in reconstituting the RichTextBox's .rtf field which is a very large string
> if you have thousands of lines. Selecting text can also be costly if you are
> using SelectionColor and/or SelectionBackColor.
>
> To get good performance with a RichTextBox, you could build the rtb's .rtf
> field (using stringbuilder) in one pass over the rtb's text looking for
> things to highlight. The prerequisite is coming to terms with the MS RTF
> specs and how they are used in a RichTextBox. Or you could try (trial and
> error) the win32 apis and messages like EM_SETCHARFORMAT. Or maybe you could
> use InkEdit which is supposed to be a superset of RichTextBox. All sound
> daunting to me.
>
> Maybe there is an alternative to RichTextBox, but I don't know what it is.
> Sorry there is no good news in this post.