c 23 how to get src from html img

1string str = "<div> <img src=\"https://i.testimg.com/images/g/test/s-l400.jpg\" style=\"width: 100%;\"> <div>Test</div> </div>";
2
3// Get the index of where the value of src starts.
4int start = str.IndexOf("<img src=\"") + 10;
5
6// Get the substring that starts at start, and goes up to first \".
7string src = str.Substring(start, str.IndexOf("\"", start) - start);
8

1var shieldHomeContainer = nodeCollection.SelectSingleNode("//img").Attributes["src"].Value;
2