Advanced C# string parse to pull specific string and substrings out of a larger string.

I have a C# string that represents HTML code.  I need to parse the string and find each instance of the img element.  Once the img element is taken out, I need to then extract the src attribute from the img element.  

Example if I have the C# string, I need to find <img src="http://www.someurl.com/image1.gif" /> and assign it to a string.  Then I need to parse the new string for the src http://www.someurl.com/image1.gif.  I am somewhat familar with C# string functions, but I am not sure how to begin working on this.

If you need more clarification please let me know.  Thank you for your help.
shanemayAsked:
Who is Participating?
I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

gdupadhyayCommented:
You can do it by regural expression easily.
Add

using System.IO;
using System.Text;
using System.Text.RegularExpressions;

Now in function you have to write following:
// File Path.
string filename = "C:\\test\\Test.txt";

string pattern = @"<img .* />";

FileStream file = new FileStream(filename, FileMode.Open, FileAccess.Read);
StreamReader sr = new StreamReader(file);
string strFileText;
strFileText = sr.ReadToEnd();
Regex re = new Regex(pattern1);
MatchCollection mc = re.Matches(strFileText);


int mIdx = 0;
string strTemp1;
string strTemp2;
foreach (Match m in mc)
{
string strTemp = m.ToString();
strTemp1 = strTemp.Replace("<img src=", "");
strTemp2 = strTemp1.Replace(" />", "");
}

The final string strTemp2 is "http://www.someurl.com/image1.gif".

I have tested this code and working fine.

Please let me know, if you have any question.

Good Luck

 
0

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
shanemayAuthor Commented:
Thank you so much for the quick response.  I really appreciate the crystal clear code example.  This is exactly what I needed,  I did not think I would have this working today.  Again, thank you so much.  
0
mkosbieCommented:
RegEx's are definitely the way to go, but the code provided is pretty cumbersome.  It won't match any img tag with more than a src attribute (eg <img src="img.jpg" id="img1">, and it does a lot of extra processing. You can extract everything you need in one pass with a function like this (this returns the sources in an arraylist):
    private ArrayList getImageSources(String HTML)
    {
        Regex re = new Regex("<img\\s[^>]*?src=[\"']([^\"']+)[\"'][^>]*>", RegexOptions.IgnoreCase);
        MatchCollection matches = re.Matches(HTML);
 
        ArrayList sources = new ArrayList();
        foreach (Match m in matches) {
            sources.Add(m.Groups[1]);
        }
 
        return sources;
    }

Open in new window

0
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today
.NET Programming

From novice to tech pro — start learning today.

Question has a verified solution.

Are you are experiencing a similar issue? Get a personalized answer when you ask a related question.

Have a better answer? Share it in a comment.