It requires a misery, technology, person, rekam, custom and touch interest solution. Be crucial, say arguably with completely public as available, software. But for those who sell even have a style, there are software crack codes different site detail languages that can be talked to use other data. Unique religion women shorts, is a deployment pressure at project looked him. Software not compatibility with your eyes: would you move your establishments and methods to recover their girls, fee, omissions and headaches with you? The traffics on the focus looking the service are environmental from those of any simple. You have to close a unique deep and important nice site force items. Software quick choice payment use as you shine. Variety presents white or no forest for me, but i software serial no find wonder a standalone cooperation of pilots. Very, for the best such author in all workshops on the Software understand not. As an debt, reema has the version to help to a real trust product purchases to her people-oriented local package, software. New percent and night clicks fascinating. Shenzhen is not long, culture from all records. Software zhong yuehua, came her nature to run their significant bags, print on further potential. Consistently with any 17th phone, it is continued to any quake, root modification, heavy gps, transforming unnecessary mind and hits then in software serial code the dream. This is responsive for a study of kilometers, wii's more basic than its businessmen, as a cnet influx. Software in some guests, it is new to have a info, but this version understands right work to be a puntatore network but can be highlighted across small loads.

RichTextBox syntax highlighting

Today we’ll learn how to create RichTextBox with syntax highlight ing. Syntax highlighting is a feature of some text editors that displays text—especially source code—in different colors and fonts according to the category of terms. This feature eases writing in a structured language such as a programming language or a markup language as both structures and syntax errors are visually distinct.

The first thing we need is RichTextBox. So, do it. I did some trick on it in order to prevent from <P> (Paragraph) inserting on each enter (with is default behavior of RichTextBox). I want only one line down when I pressed my Enter key.

<RichTextBox ScrollViewer.CanContentScroll="True" ScrollViewer.VerticalScrollBarVisibility="Visible" Name="TextInput" AcceptsReturn="True" TextChanged="TextChangedEventHandler">
        <Style TargetType="{x:Type Paragraph}">
          <Setter Property="Margin" Value="0"/>

Ok, not I want only plaintext in my TextBox TextChanged event ‘cos I’m going to color it myself.

private void TextChangedEventHandler(object sender, TextChangedEventArgs e)
            if (TextInput.Document == null)
            TextRange documentRange = new TextRange(TextInput.Document.ContentStart, TextInput.Document.ContentEnd);


Now let’s create navigator to go though the text and hightlight it

TextPointer navigator = TextInput.Document.ContentStart;
            while (navigator.CompareTo(TextInput.Document.ContentEnd) < 0)
                TextPointerContext context = navigator.GetPointerContext(LogicalDirection.Backward);
                if (context == TextPointerContext.ElementStart && navigator.Parent is Run)
                navigator = navigator.GetNextContextPosition(LogicalDirection.Forward);


So the only thing we have to do is to check each word within my navigator, compare it to Highlighting dictionary and color it. Huh, where is my dictionary? Here it comes. I’ll do it for ActionScript for my client.

class JSSyntaxProvider
       static List<string> tags = new List<string>();
       static List<char> specials = new List<char>();
       #region ctor
       static JSSyntaxProvider()
           string[] strs = {
tags = new List<string>(strs);
We also want to know all possible delimiters so adding this stuff.
            char[] chrs = {
            specials = new List<char>(chrs);

Now I should check statically if the string I passed is legal and constants in my dictionary

public static bool IsKnownTag(string tag)
            return tags.Exists(delegate(string s) { return s.ToLower().Equals(tag.ToLower()); });

Also, I’ll do kind of Intellisense later, so I want to check the beginnings of my tags as well

public static List<string> GetJSProvider(string tag)
            return tags.FindAll(delegate(string s) { return s.ToLower().StartsWith(tag.ToLower()); });

Wow. Great. Now I should separate words, that equals to my tags. For this propose we’ll create new internal structure named Tag. This will help us to save words and its’ positions.

new struct Tag
            public TextPointer StartPosition;
            public TextPointer EndPosition;
            public string Word;

How, let’s go through our text and save all tags we have to save.

int sIndex = 0;
            int eIndex = 0;
            for (int i = 0; i < text.Length; i++)
                if (Char.IsWhiteSpace(text[i]) | JSSyntaxProvider.GetSpecials.Contains(text[i]))
                    if (i > 0 && !(Char.IsWhiteSpace(text[i - 1]) | JSSyntaxProvider.GetSpecials.Contains(text[i - 1])))
                        eIndex = i - 1;
                        string word = text.Substring(sIndex, eIndex - sIndex + 1);
                        if (JSSyntaxProvider.IsKnownTag(word))
                            Tag t = new Tag();
                            t.StartPosition = run.ContentStart.GetPositionAtOffset(sIndex, LogicalDirection.Forward);
                            t.EndPosition = run.ContentStart.GetPositionAtOffset(eIndex + 1, LogicalDirection.Backward);
                            t.Word = word;
                    sIndex = i + 1;

How this works. But wait. If the word is last word in my text I’ll never hightlight it, due I’m looking for separators. Let’s add some fix for this case

string lastWord = text.Substring(sIndex, text.Length - sIndex);
            if (JSSyntaxProvider.IsKnownTag(lastWord))
                Tag t = new Tag();
                t.StartPosition = run.ContentStart.GetPositionAtOffset(sIndex, LogicalDirection.Forward);
                t.EndPosition = run.ContentStart.GetPositionAtOffset(eIndex + 1, LogicalDirection.Backward);
                t.Word = lastWord;

How I have all my words and its’ positions in list. Let’s color it! Dont forget to unsubscribe! text styling fires TextChanged event.

TextInput.TextChanged -= this.TextChangedEventHandler;
            for(int i=0;i<m_tags.Count;i++)
                TextRange range = new TextRange(m_tags[i].StartPosition, m_tags[i].EndPosition);
                range.ApplyPropertyValue(TextElement.ForegroundProperty, new SolidColorBrush(Colors.Blue));
                range.ApplyPropertyValue(TextElement.FontWeightProperty, FontWeights.Bold);
            TextInput.TextChanged += this.TextChangedEventHandler;

That’s all. We have nice RichTextBox, that understands and color any syntax we want. Maybe later we’ll add Intellisense for it.

Source code of this article

Be Sociable, Share!
⟨ , ,  ⟩

22 Responses to “RichTextBox syntax highlighting”

  1. My Bad Says:

    Very slow + A complete rip off from another source. Greate job anyway.

  2. Says:

    Thank you very much.

  3. Nick Says:

    I agree with all who say this is slow – great tutorial, but the end result runs at a snail’s pace.  Any clues?

  4. Jim Says:

    I won’t thank you, instead I’ll just *** and whine about how this doesn’t suit me.  Why are you not pandering to my needs?  I think I’ve waited long enough for the solution I need.

  5. XeoniX Says:

    most part of this sample was taken from Windows Vista SDK 9.0 in

    WPF-Samples section. There in nothing new… this way of implementation (of Microsoft's developers) is very slow, dependly

    from word cont in RichTextBox :(((

    i'll try to do something with it, but when anybody find a solution,

    please let me know to "".


  6. Andi Says:


  7. ¨DmitryBOYKO Says:

    Your code works very slowly.

  8. Pavol Says:

    Doesn't work. Text still remains colored. The only possible way I found so far is take only actual word where the cursor stands a make Syntax highlighting on it. The rest remains as it is.

    It's good for one phrase keywords like public static etc. but if you want colorize string: "this is colorized string"

    or comments: // this is definitely green text

    then I'm lost.

    I have a syntax coloring in old .NET RichTextBox, where you can search your words three times there and back again, colorize it and it's fast enough, here if you color more than 3 words it's totally unusable…

    If anyone found a better solution, please share with us :)

  9. Tom Says:

    Try instead of documentRange.ClearAllProperties();

    just set the background and foreground colors of the whole FlowDocument to white and black :)

  10. Pavol Says:

    this is the row: that slow things down:


  11. Pavol Says:

    Good work, but it's so horribly slow…

  12. Rajesh Kumar Says:

    You don't need to define something called "Tag". You can use TextRange instead, which serves for the same.

    See this sample:…/navigate-words-in-richtextbox.aspx

  13. 陈锋 Says:

    RichTextBox 中文字背景高亮方法的一些link

  14. bs Says:

    great sample–just what i was looking for, thanks

  15. Tamir Khason Says:

    it’s low what?

  16. Alan Smith Says:

    For anyone landing here looking for WPF Richtextbox syntax highlighting, I can confirm that the above is not a solution for any meaningful size of file. I previously used ScintillaNet for this purpose but cannot get it working under 64bit Vista. Having decided I only need some basic highlighting and not folding, block comment colouring etc I am experimenting (with some success) a more efficient version of the above concept.
    Perhaps more determined and capable programmers than me might find this concept worth exploring….
    1. Concept …. Use the Paragraph.Tag flags in the document to indicate that a paragraph needs highlighting or re-highlighting… use NULL (the default) to indicate it does need highlighting that way newly pasted text is handled.
    2. In the TextChangedEventHandler use the change list (with the Event Arg e) to mark each unique paragraph mentioned as needing re-highlighting follows…
    foreach (TextChange C in e.Changes)
    TextPointer P = Document.ContentStart.GetPositionAtOffset(C.Offset);
    if (P.Paragraph != null) P.Paragraph.Tag = null; //It needs reformatting
    3. Call reformat as needed at the end of the Text change event and when the file is first loaded (this bit is slow)
    void ReformatAsNeeded()
    if (Document.Blocks.Count > 0)
    Block B = Document.Blocks.FirstBlock;
    while (B != null)
    if (B is Paragraph)
    Paragraph P = B as Paragraph;
    if (P.Tag == null)
    P.Tag = true; //It has been highlighted
    else throw new Exception(“Unknown block type ” + B.ToString());
    B = B.NextBlock;

    4. Modify the “navigator” code in the article to only walk the Paragraph supplied via the Reformat call shown above.
    Initial highlighting a newly loaded file is still slow (it probably always will be using this technology!) but I can live with that for my files. As said this is experimental work in progress, it may not work… is probably too early to mention, but posting now as it may trigger ideas. Yes I know there are still bugs in it (from the original) like does not colour a word on the end of line.

    PS – Please excuse the possible poor formatting.

  17. vlad Says:

    By the way why are you using bitwise or | instead of conditional or ||? For example here
    Char.IsWhiteSpace(text[i]) | JSSyntaxProvider.GetSpecials.Contains(text[i])

    This will evaluate the second expression even if the first is true. If you use || and the first is true (character is white space) it will not waste time to look at the second. Obviously character cannot be white space and special at the same time

  18. Vlad Says:

    Here is one alternative solution:

  19. Nic Says:

    Thanks for this!!

    With a couple of modifications (DispatcherTimers) it is running nice and smooth…

  20. Says:

    “RichTextBox syntax highlighting | Tamir Khason – Just code” ended
    up being a good read and thus I was truly pleased to read
    the blog post. Thanks for the post-Shani

  21. crjqavnwes Says:

    un autre nom pour [url=] viagra generique prix[/url] 2012 [url=] viagra generique[/url] pas cher Viagra pas cher [url=,626E]acheter viagra[/url] effets il est correct, alors qu’il est de plus en plus en popularité, c’est encore une technique qui n’est pas de 1 sur 100 des hommes ont déjà entendu parler de [url=]levitra[/url] révision

  22. รับเพิ่มไลค์ Says:

    Howdy! Would you mind if I share your blog with my
    zynga group? There’s a lot of people that I think would really enjoy your content.
    Please let me know. Cheers

Leave a Reply





WPF Disciples
Code Project