CODEWITHSUNDEEP
regexvb.netstringreplace
user1634845
user1634845

Reputation:

Stripping out html tags in string

I have a program I'm writing that is supposed to strip html tags out of a string. I've been trying to replace all strings that start with "<" and end with ">". This (obviously because I'm here asking this) has not worked so far. Here's what I've tried:

StrippedContent = Regex.Replace(StrippedContent, "\<.*\>", "")

That just returns what seems like a random part of the original string. I've also tried

For Each StringMatch As Match In Regex.Matches(StrippedContent, "\<.*\>")
    StrippedContent = StrippedContent.Replace(StringMatch.Value, "")
Next

Which did the same thing (returns what seems like a random part of the original string). Is there a better way to do this? By better I mean a way that works.

Upvotes: 7

Views: 20743

Answers (3)

mikro
mikro

Reputation: 525

Here's a simple function using the regex pattern that Ro Yo Mi posted.

<Extension()> Public Function RemoveHtmlTags(value As String) As String
    Return Regex.Replace(value, "<(?:[^>=]|='[^']*'|=""[^""]*""|=[^'""][^\s>]*)*>", "")
End Function

Demonstration:

Dim html As String = "This <i>is</i> just a <b>demo</b>.".RemoveHtmlTags()
Console.WriteLine(html)

Upvotes: 1

Ro Yo Mi
Ro Yo Mi

Reputation: 15010

Description

This expression will:

  • find and replace all tags with nothing
  • avoid problematic edge cases

Regex: <(?:[^>=]|='[^']*'|="[^"]*"|=[^'"][^\s>]*)*>

Replace with: nothing

enter image description here

Example

Sample Text

Note the difficult edge case in the mouse over function

these are <a onmouseover=' href="NotYourHref" ; if (6/a>3) { funRotator(href) } ; ' href=abc.aspx?filter=3&prefix=&num=11&suffix=>the droids</a> you are looking for.

Code

Imports System.Text.RegularExpressions
Module Module1
  Sub Main()
    Dim sourcestring as String = "replace with your source string"
    Dim replacementstring as String = ""
    Dim matchpattern as String = "<(?:[^>=]|='[^']*'|=""[^""]*""|=[^'""][^\s>]*)*>"
    Console.Writeline(regex.Replace(sourcestring,matchpattern,replacementstring,RegexOptions.IgnoreCase OR RegexOptions.IgnorePatternWhitespace OR RegexOptions.Multiline OR RegexOptions.Singleline))
  End Sub
End Module

String after replacement

these are the droids you are looking for.

Upvotes: 32

user1634845
user1634845

Reputation:

Well, this proves that you should always search Google for an answer. Here's a method I got from http://www.dotnetperls.com/remove-html-tags-vbnet 

Imports System.Text.RegularExpressions

Module Module1
    Sub Main()
        Dim html As String = "<p>There was a <b>.NET</b> programmer " +
          "and he stripped the <i>HTML</i> tags.</p>"
        Dim tagless As String = StripTags(html)
        Console.WriteLine(tagless)
    End Sub
    Function StripTags(ByVal html As String) As String
        Return Regex.Replace(html, "<.*?>", "")
    End Function
End Module

Upvotes: 4

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