Can't detect '#' as special key (Regex Asp.net)

Question

I'm new on Asp. I have a problem to using regex for checking password input. Here the regex

<asp:RegularExpressionValidator ID="Regex1" runat="server" 
                    ErrorMessage="Password must contain: Minimum 8 characters atleast 1 UpperCase Alphabet, 1 LowerCase Alphabet, 1 Number and 1 Special Character" 
                    Font-Italic="True" Font-Size="Small" ForeColor="Red" 

                    ValidationExpression="^(?=.*[a-z])(?=.*[A-Z])(?=.*\d)(?=.*[$@$!%*?&amp;])[A-Za-z\d$@$!%*?&amp;]{8,}"
                    ControlToValidate="TextBoxNewPassword" Display="Dynamic" />

When I input "Hamlida123#" regex did'nt allow it. How to solve this?

Answer 1

You need to include the '#` character specifically in the regex, like so:

ValidationExpression="^(?=.*[a-z])(?=.*[A-Z])(?=.*\d)(?=.*[$@$!%*?&#])[A-Za-z\d$@$!%*?&#]{8,}"

Demo

Based on your current regex, I assume that you are only allowing certain non-word characters, and so you would need to list every allowable character in your regex as shown above.