Regular Expression for User Name

shwetha sonar14y ago

Hey,

Thanks for the reply.

The suggested regular expression does not work. It still does not meet the requirements.

Shwetha

Vulpes15y ago

It struck me subsequently that, if the user name can contain any characters, then it's no longer necessary to use 'lookahead'. I used it before when I thought that the names would probably be limited to alphanumerics or your special characters.

You could therefore simplify the regular expression to:

string regexp = @".*[^_\.]$";

Vulpes15y ago

If you don't want . or _ to appear last but, otherwise, the user name can contain absolutely anything including those characters, then you can use this:

string regexp = @"(?=.*[^_\.]$)";

shwetha sonar15y ago

Hi,

Thanks for the reply.

But, the suggested expression does not meet the requirement. It is not allowing me to enter the special characters I want (ie . and _). Also, majorly it does not accept any string for the user name. For example: only aplhabets or aplhanumeric.

Regards
Shwetha

Vulpes15y ago

Try this:

string regexp = @"^(?=.*[^_\.]+$)[A-Za-z0-9_\.]+$";