Asp.net C# Replacing all the urls of a string with an "a href" link

Question

I am currently displaying the content of a string inside a pre tag, but I have to elaborate a function that for each link into the string replace it with a link tag, I tried several string replace and regex methods, but no one worked.

string myString = "Bla bla bla bla http://www.site.com and bla bla http://site2.com blabla"
//Logic
string outputString = "Bla bla bla bla <a href="http://www.site.com" target="blank">http://www.site.com</a> and bla bla <a href="http://site2.com" target="blank">http://site2.com</a> blabla"

I have used the following code, but it does not work for every url:

string orderedString = item.Details.Replace("|", "\n" );
string orderedStringWithUrl = "";

System.Text.RegularExpressions.Regex regx = new System.Text.RegularExpressions.Regex("http://([\\w+?\\.\\w+])+([a-zA-Z0-9\\~\\!\\@\\#\\$\\%\\^\\&amp;\\*\\(\\)_\\-\\=\\+\\\\\\/\\?\\.\\:\\;\\'\\,]*)?", System.Text.RegularExpressions.RegexOptions.IgnoreCase);

System.Text.RegularExpressions.MatchCollection mactches = regx.Matches(orderedString);

foreach (System.Text.RegularExpressions.Match match in mactches)
{
    orderedStringWithUrl = orderedString.Replace(match.Value, "<a href='" + match.Value + "' target='blank'>" + match.Value + "</a>");
}

Any suggestion?

Update: I have noticed that the URLs I have in the string are all without spaces and all starts with http or https. Is it an idea the one to put into a everything that starts with http or https up to (and not included) the first space? In that case how can I use the .replace to achieve this?

Tnx in advance.

A sample would help. Probably you need to use a literal control to display the string to have it interpreted as HTML — Sascha, Aug 15 '11 at 07:14
very closely related: http://stackoverflow.com/questions/758135/c-code-to-linkify-urls-in-a-string — naveen, Aug 15 '11 at 07:17
I'm not sure I entirely understand the question; so you have a string in a tag somewhere on the page that contains a list of Urls that need to be converted with javascript? It would be very helpful if you gave a simple example of what you mean. — shelleybutterfly, Aug 15 '11 at 07:22

score 3 · Accepted Answer · answered Aug 15 '11 at 10:19

In a sample I used this markup

<body>
    <form id="form1" runat="server">
    <div>
      <asp:Literal ID="litTextWithLinks" runat="server" />
    </div>
    </form>
</body>

along with that code-behind

private const string INPUT_STRING = "Bla bla bla bla http://www.site.com and bla bla http://site2.com blabla";

protected void Page_Load ( object sender, EventArgs e ) {
  var outputString = INPUT_STRING;

  Regex regx = new Regex( @"https?://([-\w\.]+)+(:\d+)?(/([\w/_\.]*(\?\S+)?)?)?", RegexOptions.IgnoreCase );

  MatchCollection mactches = regx.Matches( INPUT_STRING );
  foreach ( Match match in mactches ) {
    outputString = outputString.Replace( match.Value, String.Format( "<a href=\"{0}\" target=\"_blank\">{0}</a>", match.Value ) );
  }

  litTextWithLinks.Text = outputString;
}

For all URLs from your sample where correctly replaced with links that opened in a new browser window.

You could test the url by doing a WebRequest and only replacing if opening succeeds. If not all URLs match, then you probably need to change the regular expression.

If this doesn't answer your question, you should add some more detail.

It works, but not entirely. It does not work with url with "-" or ?ID=1988& and some other cases. I've updated my answer with a possible thing to filter all these regex filter, any idea on how to do it? — Attila, Aug 15 '11 at 10:57
Try using this regex: https?://[^\s]* http followed by an optional s followed by :// followed by anything that is now whitespace — Sascha, Aug 15 '11 at 11:03

score 0 · Answer 2 · answered Aug 15 '11 at 07:13

0

check this out: http://alexlittle.net/blog/2009/06/26/regex-for-replacing-url-with-anchor-tag/

answered Aug 15 '11 at 07:13

Waqas

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Asp.net C# Replacing all the urls of a string with an "a href" link

2 Answers2