using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text.RegularExpressions;
 
public class Test
{
	public static void Main()
	{
		var text = "[MYLINK ID=\"1234\" URL=\"http://m...content-available-to-author-only...e.com\" TEXT=\"Website link\"]";
		var pattern = "\\[MYLINK\\s+ID=\"([^\"]*)\"\\s+URL=\"([^\"]*)\"\\s+TEXT=\"([^\"]*)\"]";
		var replacement = "<a href=\"$2?id=$1\">$3</a>";
		var result = Regex.Replace(text, pattern, replacement, RegexOptions.IgnoreCase);
	   	Console.WriteLine(result);
	}
}

dXNpbmcgU3lzdGVtOwp1c2luZyBTeXN0ZW0uQ29sbGVjdGlvbnMuR2VuZXJpYzsKdXNpbmcgU3lzdGVtLklPOwp1c2luZyBTeXN0ZW0uTGlucTsKdXNpbmcgU3lzdGVtLlRleHQuUmVndWxhckV4cHJlc3Npb25zOwoKcHVibGljIGNsYXNzIFRlc3QKewoJcHVibGljIHN0YXRpYyB2b2lkIE1haW4oKQoJewoJCXZhciB0ZXh0ID0gIltNWUxJTksgSUQ9XCIxMjM0XCIgVVJMPVwiaHR0cDovL20uLi5jb250ZW50LWF2YWlsYWJsZS10by1hdXRob3Itb25seS4uLmUuY29tXCIgVEVYVD1cIldlYnNpdGUgbGlua1wiXSI7CgkJdmFyIHBhdHRlcm4gPSAiXFxbTVlMSU5LXFxzK0lEPVwiKFteXCJdKilcIlxccytVUkw9XCIoW15cIl0qKVwiXFxzK1RFWFQ9XCIoW15cIl0qKVwiXSI7CgkJdmFyIHJlcGxhY2VtZW50ID0gIjxhIGhyZWY9XCIkMj9pZD0kMVwiPiQzPC9hPiI7CgkJdmFyIHJlc3VsdCA9IFJlZ2V4LlJlcGxhY2UodGV4dCwgcGF0dGVybiwgcmVwbGFjZW1lbnQsIFJlZ2V4T3B0aW9ucy5JZ25vcmVDYXNlKTsKCSAgIAlDb25zb2xlLldyaXRlTGluZShyZXN1bHQpOwoJfQp9