The incredibly awesome AvalonEdit WPF TextEditor control seems to lack an important feature, or at least i can't figure it out. Given an offset and a length, highlight that portion in the TextDocument with a HighlightColor. Simple, right?
Apprentely not. I've RTFM, and the documentation on "Syntax Highlighting" confused me even more. Someone else asked the same question in the SharpDevelop forums, and i'm afraid i can't make sense of Herr Grunwald's answer.
Here's my attempt, using the DocumentHighlighter class (of course it doesn't work):
textEditor1.Text = "1234567890";
HighlightingColor c = new HighlightingColor() { FontWeight = FontWeights.ExtraBold };
DocumentHighlighter dh = new DocumentHighlighter(textEditor1.Document, new HighlightingRuleSet());
HighlightedLine hl = dh.HighlightLine(1);
hl.Sections.Add(new HighlightedSection() { Color = c, Offset = 1, Length = 3 });
Thank you for helping!
Did you see this in this article - it seems to be exactly what are you asking for:
public class ColorizeAvalonEdit : DocumentColorizingTransformer
{
protected override void ColorizeLine(DocumentLine line)
{
int lineStartOffset = line.Offset;
string text = CurrentContext.Document.GetText(line);
int start = 0;
int index;
while ((index = text.IndexOf("AvalonEdit", start)) >= 0) {
base.ChangeLinePart(
lineStartOffset + index, // startOffset
lineStartOffset + index + 10, // endOffset
(VisualLineElement element) => {
// This lambda gets called once for every VisualLineElement
// between the specified offsets.
Typeface tf = element.TextRunProperties.Typeface;
// Replace the typeface with a modified version of
// the same typeface
element.TextRunProperties.SetTypeface(new Typeface(
tf.FontFamily,
FontStyles.Italic,
FontWeights.Bold,
tf.Stretch
));
});
start = index + 1; // search for next occurrence
} } }
It highlights word AvalonEdit with bold.