Bold selective text from string based on start/end position

Question

In my ASP.NET page, I have a string (returned from SQL db). I would like to bold certain part of the string text based on given text position.

For example, if I have a string as follows:

"This is an example to show where to bold the text"

And I am given character start position: 6 and end position: 7, then I would bold the word "is" in my string, getting:

"This is an example to show where to bold the text"

Any ideas?

EDIT: Keep in mind I need to use the start/end position as there may be duplicate words in the string.

Answer 1

1. Insert a close tag into position 7 of the string
2. Insert an open tag into position 5 (6 - 1) of the string.
3. You will get a string like "This is an example…"

I.e. modify string (insert markup) from end to start:

var result = str.Insert(7, "</b>").Insert(6 - 1, "<b>");