Examples for ComboBox mask

I would like to use a ComboBox and it doesn’t have the mask property. I am interested in restricting the entry to ASCII. Are there example out there of setting a mask in Keydown?

Define “restricting to ASCII”
if you mean only characters from 0x00 to 0x7F then

return (ASCB(key)>&H7F)

if you mean something else

Thanks. I was wondering if there were more complicated examples or considerations. The reason I ask the question is because sometimes I miss possibilities. With GetTempFolderItem, I didn’t realize I could complete it with something as simple