using System;
using System.Text.RegularExpressions;
public class Example
{
public static void Main()
{
string pattern = @"(?<!\S)#([0-9a-zA-Z]+)";
string substitution = @"<a href=""/hashtag/$1"">#$1</a>";
string input = @"#ত্বকের উজ্জ্বলতা কী?
#কীভাবে ধরে রাখবেন উজ্জ্বলতা?
#PRP (Vampire Facial) #Chemical Peel #Oxyfacial #Hydrafacial #Glutathione Injection";
RegexOptions options = RegexOptions.IgnoreCase;
Regex regex = new Regex(pattern, options);
string result = regex.Replace(input, substitution);
}
}
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for C#, please visit: https://msdn.microsoft.com/en-us/library/system.text.regularexpressions.regex(v=vs.110).aspx