CODEWITHSUNDEEP
asp.netregexvb.net
Sameer
Sameer

Reputation: 705

Replace all URLs with hyperlinks

I have following code which uses regex to find all the urls within a given string:

Dim regex As New Regex("(http(s)?:\/\/.)?(www\.)?[-a-zA-Z0-9@:%._\+~#=]{2,256}\.[a-z]{2,6}\b([-a-zA-Z0-9@:%_\+.~#?&//=]*)", RegexOptions.IgnoreCase)

Now, I want to replace all the matches with hyperlinks:

For Each match As Match In mactches
    strtemp &= strtemp.Replace(match, "<a target='_blank' href='mailto:" & match & "'>" & match & "</a>")
Next

The regex works fine but there is an issue while replacing. Suppose my input string is as follows:

www.google.com is as same as google.com and also http://google.com

The code will first replace www.google.com with <a> and then, when the second match (google.com) comes up, it will again replace the previous one. So, what is a way of achieving this?

Upvotes: 2

Views: 523

Answers (1)

Steven Doggart
Steven Doggart

Reputation: 43743

If you use Regex.Replace, it will work correctly, since it will replace each occurrence as it finds them rather than replacing all other matches at the same time:

Dim pattern As String = "(http(s)?:\/\/.)?(www\.)?[-a-zA-Z0-9@:%._\+~#=]{2,256}\.[a-z]{2,6}\b([-a-zA-Z0-9@:%_\+.~#?&//=]*)"
Dim regex As New Regex(pattern, RegexOptions.IgnoreCase)
Dim input As String = "www.google.com is as same as google.com and also http://google.com"
Dim output As String = regex.Replace(input, "<a target='_blank' href='mailto:$&'>$&</a>")

However, if you are just going to recreate the Regex object each time you call it, you could just use the static Regex.Replace method instead.

The $& is a special substitution expression which instructs the Replace method to insert the entire match at that point in the replacement string. For other substitution expressions, see the section on the MSDN quick reference page.

Upvotes: 4

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