validation of C#

Question

I am using C#. I am making validation and I have some problems with the id card number and license plate number. The id card number it has to be: validated to ensure that the user input contains no more than six digits and single letter at the end (‘M’ or ‘G’) The license plate number it has to be: the client should input 3 different license plates, first one input being the most preferred. All three license plates input should be validated to confirm with the standard license plate format(i.e. CCC-DDD, where C = character and D = digit) Looking forward to reply soon thanks