How can I optimize this or is there a better way to do it?(HTML Syntax Highlighter)
Question
I have made a HTML syntax highlighter in C# and it works great, but there's one problem. First off It runs pretty fast because it syntax highlights line by line, but when I paste more than one line of code or open a file I have to highlight the whole file which can take up to a minute for a file with only 150 lines of code. I tried just highlighting visible lines in the richtextbox but then when I try to scroll I can't it to highlight the new visible text. Here is my code:(note: I need to use regex so I can get the stuff in between < & > characters)
Highlight Whole File:
public void AllMarkup()
{
int selectionstart = richTextBox1.SelectionStart;
Regex rex = new Regex("<html>|</html>|<head.*?>|</head>|<body.*?>|</body>|<div.*?>|</div>|<span.*?>|</span>|<title.*?>|</title>|<style.*?>|</style>|<script.*?>|</script>|<link.*?/>|<meta.*?/>|<base.*?/>|<center.*?>|</center>|<a.*?>|</a>");
foreach (Match m in rex.Matches(richTextBox1.Text))
{
richTextBox1.Select(m.Index, m.Value.Length);
richTextBox1.SelectionColor = Color.Blue;
richTextBox1.Select(selectionstart, -1);
richTextBox1.SelectionColor = Color.Black;
}
richTextBox1.SelectionStart = selectionstart;
}
private void pasteToolStripMenuItem_Click(object sender, EventArgs e)
{
try
{
LockWindowUpdate(richTextBox1.Handle);//Stops text from flashing flashing
richTextBox1.Paste();
AllMarkup();
}finally { LockWindowUpdate(IntPtr.Zero); }
}
I want to know if there's a better way to highlight this and make it faster or if someone can help me make it highlight only the visible text.
Please help. :) Thanks, Tanner.
1 answers
solution1
1 2010-05-12 15:37:22
I agree with RCIX - you'll have a hard time overall with combining Regex and HTML parsing :)
If you're going for a high-quality solution that always highlights syntax properly, you're going to need a full-blown parser. You can either use one that's already created, or you can create your own using a tool like ANTLR .
The creators of ANTLR have already created an HTML parser grammar. You can find it here .
If you're looking for a pre-built one, here's a few I've found:
I'm sure there are others -- this is a pretty common requirement.
Long story short, if this is anything but a simple, disposable project, I'd get a full-blown parser. Otherwise, you can continue to try and hack it with Regex.
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