Visual Basic Empty String vs. Blank Space

The problem with your 'Cancel' button not

working with your input box, I suspect is

from this line here where you're assigning

a blank space to the strCancelClicked variable

You're assigning a blank space. What's

actually in the input box when you click

the 'Cancel' button is 'no character' or

what is what we call an empty string.

Now I've actually tested this and I want to

test it and show you how I tested it.

I test by setting a break point at
the 'Do Until' loop.

I'm going to run or debug your program

when the program code gets to this line

it will pause, we can actually look at

the values in each of these variables and

so what I'll do is run your program, I'll

enter two values for temperatures and then

for the third input I'll click the 'Cancel'

button. But after each value I input the

program is going to pause at this line

and allows us to look at the variables and

then we can continue on until the next

input and so on.

I'll start debugging. Enter the
temperature for month number 1.

Click the 'OK' button. The program code

pauses here. I can see the number of

entries is one. Of course the max entries

should be 12. The strTemp is 98, that's

what I entered and the strCanceled is

you can faintly see it there
'quote' 'space' 'quote'.

Again that's exactly what you assigned it.

Now I can continue the program code by

clicking the F5 or if we wanted to we

could go line by line by clicking the F8 key.

But we are just going to continue.

The program is going to prompt me for

month #2. Again we pause, the number of

entries is now 2, max number of entries

should stay at 12. What I entered into

the input box is 99 and again the

strCanceledClick is the 'space'.

One more continue. For the third

temperature I'm going to click the

'Cancel' button. Now the program again

pauses here, third entry, notice this

strTemp is 'quote' 'quote' but

strCanceled is 'quote' 'space' 'quote'.

That's why when we continue our program

you are prompted to enter a number of

months instead of it canceling. So what

I'm going to do is actually stop the

program, say 'Yes' you're not cancelling

out because of the blank space here. You

get rid of the blank space, I'm also going

to remove the break point. We're going

to run the program again. Now strCenceled

will equal the empty string. Again I'll

enter two temperatures, notice there's no

break point so it's not pausing the code.

For the third temperature I click 'Cancel'

and it breaks out of the loop, averages

the two temperatures, displays it,

the program is working fine.

I hope that you understand now the

difference between an empty string
and a blank space.