Regular expressions and C# - replace pattern with pattern

Question

Sorry, my questions are not so difficult. But can't find answers how to work with Regular Expressions in C#.

What mean sign @ before blockquote in C# Regex?

And how to replace pattern with pattern? For example replace <img ...> with [img ....]

 

 

Answer 1

Have found this:

   string mes;
           mes = "<img>";

            mes = Regex.Replace(mes, @"<img*>", delegate(Match match)
            {
                string v = match.ToString();
                return "[" + v[1] + "]";
            });

            MessageBox.Show(mes);

but what to place in v[1]?

Couse img tag can have some attributes inside...

 

Answer 2

Have found. May be will gonna use something like this:

           string mes;
           mes = "<h1 style= >";

           string res;
            res = Regex.Replace(mes, @"<h1.*>", delegate(Match match)
            {
                string v = match.ToString();
                return "<" + v.Substring(4,v.Length-8)+">";
             
            });

            MessageBox.Show(res);

Answer 3

> And how to replace pattern with pattern? For example replace <img ...> with [img ....]
 
   

var re = new Regex("<(?<tag>img.+?)>",  RegexOptions.IgnoreCase | RegexOptions.Singleline | RegexOptions.Compiled);
var str = re.Replace("text <img src='some'> text", "[${tag}]");

  

Answer 4

Thank you!

And I have write such one:

 

messs = createHTML(messs, "<img[a-zA-z0-9\t\n .:;=\"/]*>");

and:

 

 

   string createHTML(string mes,string pattern){
       string res;

       res = Regex.Replace(mes, @pattern, delegate(Match match)
       {
           string v = match.ToString();
           return "<" + v.Substring(4, v.Length - 8) + ">";

       },RegexOptions.IgnoreCase);

       return res;

    }

But now I thinking about how to check that string does not contained JavaScript?

 

Add match inside delegate? Not a cute code....

Answer 5

> createHTML(messs, "&lt;img[a-zA-z0-9\t\n .:;=\"/]*&gt;"); [...] Add match inside delegate? ...
 
 
 

   

var html = createHTML("<img src='url' >\n<br/>");
...

string createHTML(string str)
{
    MatchEvaluator me = m => string.Concat("<", m.Groups["tag"].Value, ">");
    return Regex.Replace(str, "&lt;(?<tag>.+?)(&gt;|>)", me, 
        RegexOptions.IgnoreCase | RegexOptions.Singleline | RegexOptions.Compiled);
}

 

Answer 6

> But now I thinking about how to check that string does not contained JavaScript?

 

var re = new Regex(@"(<|&lt;|&\#60;)script\b",
    RegexOptions.IgnoreCase | RegexOptions.Singleline | RegexOptions.Compiled);

 

Answer 7

Yea, that's right. But I want to check this at the same regex where i searching for img.

I think that your first reply is the best. Gonna try it now... 

Answer 8

Will mark your answer as answer. ))

But in code better will use my pattern.  I have add here ? - couse there can be some chars after img or can be not

"<img[a-zA-z0-9\t\n -.:;=\"/]*?>"

 

 

 

 

Answer 9

> But I want to check this at the same regex where i searching for img.  
 
  
could you please provide some of the possible texts?
but i think it would be better to work with standalone patterns.
and do search matches in parallel.
  
  

Answer 10

Sorry that so late.

Offcourse I can! ) It's simple easy:

"&lt;img src="javascript:alert('css');"&gt;"

So, I want to replace when text match pattern "&lt;(?<tag>.+?)(&gt;|>)" and not contained "script" at the same time.

Have found conditional OR | but can't find AND... Anyway, thank you Malobukv you have helped! ( ty napisal ne tak uj i malo bukv ))