删除HTML标记，但不使用正则表达式C＃

Question

I wanted to strip all the html but preserve <b> tags using regex. Is there a better way to do instead of

1. Replace <b> with a non html tag like $b$
2. Remove all html tags using <[^>]*>
3. Replace $b$ with <b>

Answer 1

Below is one approach that will only permit opening and closing b tags. Any other tags are removed.

var teststring = "Test <b>test</b> lorem <i>ipsum</i>";
var pattern = @"(?!</?b>)<.*?>"; // assuming open and closing tags are retained
Console.WriteLine(Regex.Replace
       (teststring,
         pattern,
         String.Empty,
         RegexOptions.Multiline));

Outputs: Test <b>test</b> lorem ipsum