RemoveInvalidPathChars

public static string RemoveInvalidPathChars(string s) {
            if(s == null)
                return null;
            char[] invalid = Path.GetInvalidPathChars();
            string result = string.Empty;
            for(int i = 0;i < s.Length;i++) {
                char c = s[i];
                if(invalid.Contains(c))
                    continue;
                result += c.ToString();
            }
            return result;
        }
        public static string RemoveInvalidFileNameChars(string s) {
            if(s == null)
                return null;
            char[] invalid = Path.GetInvalidFileNameChars();
            string result = string.Empty;
            for(int i = 0;i < s.Length;i++) {
                char c = s[i];
                if(invalid.Contains(c))
                    continue;
                result += c.ToString();
            }
            return result;
        }