<asp:RegularExpressionValidator ValidationGroup="Anagrafica" ID="RegularExpressionValidatorEmail"
                                                    ControlToValidate="TextBoxEmail" ValidationExpression="\w+([-+.']\w+)*@\w+([-.]\w+)*\.\w+([-.]\w+)*"
                                                    ErrorMessage="Indirizzo email immesso non valido" EnableClientScript="true" runat="server" />

//Email regex validator
Regex regex = new Regex(@"\w+([-+.']\w+)*@\w+([-.]\w+)*\.\w+([-.]\w+)*");
 
//Website regex validator
Regex regex = new Regex(@"^http\://[a-zA-Z0-9\-\.]+\.[a-zA-Z]{2,3}(/\S*)?$");
 
//Comments on forum regex validator (max 4000 characters)
Regex regex = new Regex(@"^[+_%@:,.'!?"\\\^\&\#\$\*\(\)\-\/a-zA-Z0-9\s]{1,4000}$");

var text = "I (Iceland) Found (Faroe Islands) the Needles (Norway) South (Sweden) of Finland (Finland). Drinks (Denmark) for Everyone (Estonia) Laughed (Latvia) the Little (Lithuania) Neanderthal (Northern Ireland) Selling (Scotland) English (England) Wales (Wales) Inside (Ireland) Northern Europe";
var rg = new Regex(@"\([^)]*\)", RegexOptions.IgnorePatternWhitespace);
var replacedStr = rg.Replace(text,"");

using System;
using System.Drawing;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;
using System.Data;
using System.Text.RegularExpressions;
using System.Text;
using System.IO;
using System.Reflection;