Design of your data types should not depend on way how they displayed by controls (or saved to data storage). If I see property of type byte
then it tells me what range of values my data type expects. E.g. Color
class has self-descriptive properties R,G,B
of type byte
.
Also do not do premature optimizations - if it become performance problem (I have doubts that casting from byte to int could have big influence on system performance) then you can optimize problem code later.
BTW casting from byte to int is implicit, so you don't need to do it manually:
comboBox.SelectedIndex = myObj.ByteProperty;