Design a form that allows a user to do simple arithemtic.
The user can select an operation (addition, subtraction of multipication)
from a combobox. When this is done, the button displays the
symbol that corresponds to the operation and any answer from
the previous operation is cleared out.
The user can enter numbers in the textboxes. Any change to what is in
the textbox should clear out any previous answer.
When the user clicks on the button with the operation symbol, the
operation is performed and the answer in placed at the bottom. (I used a
Read-Only textbox, but a label would also work.)
If the user enters a value that is not a number, have a messagebox
tell him or her, clear out the offending textbox and place the cursor
in it.
If the Integers only checkbox is checked, then the numbers in the textbox
should be replaced by integers. In this case I used CInt() to get a variable from
the textbox, then I placed this result back in the textbox.
I had the CheckChanged event method call the button's click event using the
following line of code:
