To check valid email id syntax,for all id of textbox in C#

System.Text.RegularExpressions.Regex rEMail = new System.Text.RegularExpressions.Regex(@"^[a-zA-Z][\w\.-]{2,28}[a-zA-Z0-9]@[a-zA-Z0-9][\w\.-]*[a-zA-Z0-9]\.[a-zA-Z][a-zA-Z\.]*[a-zA-Z]$");

 if (rEMail.IsMatch(tb.Text))
 {
  // other codes...
 }
 else 
 {
 // alert for wrong email id syntax
 }

bool isEmail = Regex.IsMatch(TextBox1.Text, @"Put your regex expression here")

<asp:RegularExpressionValidator ID="RevEMail" runat="server" ControlToValidate="txtEmailID" Display="Dynamic" ErrorMessage="is not valid" SetFocusOnError="true"  ValidationExpression="[a-z0-9!#$%&'*+/=?^_`{|}~-]+(?:\.[a-z0-9!#$%&'*+/=?^_`{|}~-]+)*@(?:[a-z0-9](?:[a-z0-9-]*[a-z0-9])?\.)+(?:[A-Z]{2}|com|org|net|edu|gov|mil|biz|info|mobi|name|aero|asia|jobs|museum)\b"></asp:RegularExpressionValidator>

public static bool CheckValidEmailAddress(string emailID)
       {
           string pattern = @"^([a-zA-Z0-9_\-\.]+)@((\[[0-9]{1,3}" +
                 @"\.[0-9]{1,3}\.[0-9]{1,3}\.)|(([a-zA-Z0-9\-]+\" +
                 @".)+))([a-zA-Z]{2,4}|[0-9]{1,3})(\]?)$";
           Regex regularExpression = new Regex(pattern);
           return regularExpression.IsMatch(emailID);

       }