Validate input in textbox

[anb001]

I have a textbox where I need an afterupdate event, which should check that input is 3 letters followed by 3 numbers. The total is 6 characters, but always 3 letters + 3 numbers.

If condition not met, a msgbox will be shown, for the user to input correctly, before being able to continue.

Can someone help with code about checking for the letters+numbers?

Thanks.

 

[bob fitz]

FYI Validation code should be it the Before Update event which can be cancelled if validation fails.
In this case perhaps you could simply set the "Input Mask" property of the text box to: LLL000