tags:

views:

350

answers:

5
Q: 

Using RegEx Replace function in C# ASP.NET

How do I solve the problem below?

I'm creating a simple content management system, where there is a HTML template with specific markup that denotes where content should be:

<html><head></head><body><!-- #Editable "Body1" --><p>etc etc</p><!-- #Editable "Extra" --></body></html>

Separate from this, there is content in a database field that looks a little like this:

<!-- #BeginEditable "Body1" -->This is Test Text<!-- #EndEditable --><!-- #BeginEditable "Extra" -->This is more test text<!-- #EndEditable -->

As you can guess I need to merge the two, that is, replacing

<!-- #Editable "Body1" -->

with:

This is Test Text

I've begun the code here. But I'm having problems using the Regex Replace function that should be located at the very bottom of that For/Each....

    //Html Template
    string html = "<html><head></head><body><!-- #Editable \"Body1\" --><p>etc etc</p><!-- #Editable \"Extra\" --></body></html>";        

    //Regions that need to be put in the Html Template
    string regions = "<!-- #BeginEditable \"Body1\" -->This is Test Text<!-- #EndEditable --><!-- #BeginEditable \"Extra\" -->This is more test text<!-- #EndEditable -->";

    //Create a Regex to only extract what's between the 'Body' tag
    Regex oRegex = new Regex("<body.*?>(.*?)</body>", RegexOptions.Multiline);

    //Get only the 'Body' of the html template
    string body = oRegex.Match(html).Groups[1].Value.ToString();

    // Regex to find sections inside the 'Body' that need replacing with what's in the string 'regions'
    Regex oRegex1 = new Regex("<!-- #Editable \"(.*?)\"[^>]*>",RegexOptions.Multiline);
    MatchCollection matches = oRegex1.Matches(body);

    // Locate section titles i.e. Body1, Extra
    foreach (Match match in matches)
    {
        string title = oRegex1.Match(match.ToString()).Groups[1].ToString();
        Regex oRegex2 = new Regex("<!-- #BeginEditable \"" + title + "\"[^>]*>(.*?)<!-- #EndEditable [^>]*>", RegexOptions.Multiline);
        //
        //
        // Replace the 'Body' sections with whats in the 'regions' string cross referencing the titles i.e. Body1, Extra
        //
        //
        //
    }
A: 

It might be better to use the Html Agility Pack to deal with this for you then resorting to regex's. It can parse Html into a XML like tree in a DOM structure, and it would be easier to handle this problem using this pack.

Edit:

string sReg = @"<body.*?>((?<Region>\<\!\-\-\s+\#Editable\s?\\$(?<editable>.+)\\$\s?\-\-\>[^\>]).*?)";
string sNewReg = sReg1.Replace('$', '\"');            System.Diagnostics.Debug.WriteLine(string.Format("Regex: {0}", sNewReg))
Regex MyRegex = new Regex(sNewReg,
    RegexOptions.IgnoreCase
    | RegexOptions.CultureInvariant
    | RegexOptions.IgnorePatternWhitespace
    | RegexOptions.Compiled
    );
string sMg = "<html><head></head><body><!-- #Editable \\\"Body1\\\" --><p>etc etc</p><!-- #Editable \\\"Extra\\\" --></body></html>";
Match m = MyRegex.Match(sMg);
if (m.Success)
{
  System.Diagnostics.Debug.WriteLine(string.Format("{0}", m.Groups["editable"].Value));
}

Note how I had to use the dollar sign in place to prevent escaping, and replace it with a double quote at runtime..

Hope this helps, Best regards, Tom.

tommieb75  2010-02-18 11:01:18
I'm time limited a only one line of code away from success! ;(
Stephen  2010-02-18 11:11:26
A: 

I would suggest using a templating engine like NVelocity for this kind of stuff.

Sorin Comanescu  2010-02-18 11:05:00
I'm time limited a only one line of code away from success! :(
Stephen  2010-02-18 11:07:18
... and a few regexes away from perpetual maintenance...
Sorin Comanescu  2010-02-18 11:08:45
More than one line I'm afraid
andynormancx  2010-02-18 11:11:19
ok probably three
Stephen  2010-02-18 11:12:01
+2  A: 

Not optimized for performance (or anything else) but it's simple and works :

var html = "<html><head></head><body><!-- #Editable \"Body1\" --><p>etc etc</p><!-- #Editable \"Extra\" --></body></html>";
var regions = "<!-- #BeginEditable \"Body1\" -->This is Test Text<!-- #EndEditable --><!-- #BeginEditable \"Extra\" -->This is more test text<!-- #EndEditable -->";
var regionRegex = new Regex(@"<!-- #BeginEditable ""(?<Name>\w+)"" -->(?<Content>.*?)<!-- #EndEditable -->", RegexOptions.Multiline);
var regionMatches = regionRegex.Matches(regions);

foreach (Match regionMatch in regionMatches)
{
    var regionName = regionMatch.Groups["Name"].Value;
    var regionContent = regionMatch.Groups["Content"].Value;
    html = html.Replace(string.Format(@"<!-- #Editable ""{0}"" -->", regionName), regionContent);
}
Diadistis  2010-02-18 11:20:02
Perfect, you put me to shame!
Stephen  2010-02-18 11:31:28
BTW, you should promote `regionRegex` to private static field and append the `RegexOptions.Compiled` flag. Also use `StringBuilder` to do the replacements inside the loop.
Diadistis  2010-02-18 11:37:40
Thanks a mill... spot on, i love the simplicity.
Stephen  2010-02-18 11:40:45
A: 

use MatchEvaluator as anonymous delegate your code will be looks like

string html = "<html><head></head><body><!-- #Editable \"Body1\" --><p>etc etc</p><!-- #Editable \"Extra\" --></body></html>";
string regions = "<!-- #BeginEditable \"Body1\" -->This is Test Text<!-- #EndEditable --><!-- #BeginEditable \"Extra\" -->This is more test text<!-- #EndEditable -->";

Regex oRegex1 = new Regex("<!-- #Editable \"(.*?)\"[^>]*>", RegexOptions.Multiline);

html = oRegex1.Replace(html, delegate(Match m) {
    string title = m.Groups[1].Value;
    Regex oRegex2 = new Regex("<!-- #BeginEditable \"" + title + "\"[^>]*>(.*?)<!-- #EndEditable [^>]*>", RegexOptions.Multiline);
    return oRegex2.Match(regions).Groups[1].Value;
});
necrostaz  2010-02-18 11:23:47
A: 

Tom, Where can I find tutorial documentation for HTML Agility Pack. I realize that there is "documentation" included with the download, but it is quite terse and seems to be intended more as a reference for experienced users than as a tool for learning the HTML Agility Pack.

 2010-03-10 06:13:46

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