RegularExpressionValidator for multiple emails.

Question

I'm validating a textbox for valid email with this:

<asp:RegularExpressionValidator ID="RegularExpressionValidator1"
ControlToValidate="txtMailCustom"
Text="Invalid address"
ValidationExpression="^([a-zA-Z0-9_\-\.]+)@((\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]
{1,3}\.)|(([a-zA-Z0-9\-]+\.)+))([a-zA-Z]{2,4}|[0-9]{1,3})(\]?)$" runat="server" />

Now I want users to be able to put multiple email addresses , separated by a comma and space.

How can I integrate that behaviour ?

Answer 1

I should do this: what it does is check for at least one mail, and for list of email before it with each a comma and possibly a space.

^(([a-zA-Z0-9_\-\.]+)@((\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.)|(([a-zA-Z0-9\-]+\.)+))([a-zA-Z]{2,4}|[0-9]{1,3})(\]?), ?)*^([a-zA-Z0-9_\-\.]+)@((\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.)|(([a-zA-Z0-9\-]+\.)+))([a-zA-Z]{2,4}|[0-9]{1,3})(\]?)$

Use this if the space between each mail is required:

^(([a-zA-Z0-9_\-\.]+)@((\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.)|(([a-zA-Z0-9\-]+\.)+))([a-zA-Z]{2,4}|[0-9]{1,3})(\]?), )*^([a-zA-Z0-9_\-\.]+)@((\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.)|(([a-zA-Z0-9\-]+\.)+))([a-zA-Z]{2,4}|[0-9]{1,3})(\]?)$

Note I just used your single mail checker as a base and didn't really edit it.

Answer 2

try this expression:

^(\s*,?\s*[0-9a-zA-Z]([-.\w]*[0-9a-zA-Z])*@([0-9a-zA-Z][-\w]*[0-9a-zA-Z]\.)+[a-zA-Z]{2,9})+\s*$