asp.net validations

I want to add a validation control to check if the first name and last name of a person entered consists of characters from A-Z and not any special characters and numbers? How to do it?

From stackoverflow

• You could use a Regular Expression validator or a Custom Validator.

• use a regular expression validator and put the [a-zA-Z] as the reg ex to validate.
  If you want support for hyphen and underscore then put [a-zA-Z_\-]

  <asp:RegularExpressionValidator id="revalApha" runat="server" 
  ControlToValidate="TextBox1" ValidationExpression="[a-zA-Z]+$" 
  ErrorMessage="Only Alphabets allowed"> </asp:RegularExpressionValidator>
  

  I will advice against the custom validator since you need to write a function both in javascript and in c#

• Here is a good example of using a regular expression validator for that. But don't forget O'Dell and Van Damme. :)