I need to ask some questions about that calculator,you know I' m a newhand.
my problem is like following:
when I want to input a number ,for instance, 123
When I click button 1 ,txextBox will diaplay 1
when I click button 2 ,textbox will display 2,but at the same time the number 1 will disappear.etc.
How I can solve this problem?
Thank you very much!