Choosing their username for them

[chris1979]

I have two custom fields on my registration form - one is for their firstname and the other for their lastname.

I want their username to always be firstname_lastname (or customfield1_customfield2). Is there a way to make that happen automatically?

[Dismounted]

You could overwrite the username variable just before it is inserted into the database via plugins.

[chris1979]

How would I do that?

[Dismounted]

Create a plugin at register_addmember_process, overwriting whatever the username variable is.

[Videx]

If you're an expert coder you can do it fairly easily. If you're like most of the rest of us, the answer to your original question is 'no'.

In fact, I don't think you can do it anyway in a practical sense. Some things just don't have a software solution. What would stop someone from entering "John <space>" and becoming just "John " on your board?