Regex to validate filename

Answer 1

using System.Linq;
using System.IO;

string path = ...;

IEnumerable<char> invalidChars = Enumerable.Concat(
    Path.GetInvalidFileNameChars(),
    Path.GetInvalidPathChars());

foreach (char c in invalidChars)
{
    path = path.Replace(c, ''); // or any char you want
}

Answer 2

resultString = Regex.Replace(subjectString, @"[^a-zA-Z0-9!@$%^&*()_+=[\]{}';,.-]", "X");

should do it.

Explanation: I copied your list of characters and pasted them into a negated character class ([^...]). I just had to make two minor modifications: Escaping the closing bracket (\]) and putting the dash at the end of the string.