calculation problem

[shanehenery]

Hi

It is a calculating form to indicate on how many books you bay and the total discount you will get after you click calculate
it is not all the coding in the hole form
just the calculate part
It is not calculating the 15% discount
DiscountTextBox
, discount price
DiscountedTextBox
it only gifs me a 0.00 amount

ore any of the calculations in the summary group box
QuantitySumTextBox
DiscountSumTextBox
DiscountedAmountSumTextBox
AverageDiscountTextBox
is not calculating at all

Private Sub> CalculateButton_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles CalculateButton.Click
'Calculate the price and discount
Dim QuantityInteger As Integer
Dim PriceDecimal, ExtendedPriceDecimal, DiscountDecimal, DiscountedPriceDecimal, AverageDiscountDecimal, _
DISCOUNT_RATE_Decimal, ExtendedPriceDecilmal, QuantitySumInteger, DiscountSumDecimal, SaleCountInteger, _
DiscountedSumDecimal, AverageDescountDecimal As Decimal
Try
'Convert quantity to numeric variable
QuantityInteger = Integer.Parse(QuantityTextBox.Text)
Catch ex As Exception
End Try
Try
'Convertprice if quantity was successful.
PriceDecimal = Decimal.Parse(PriceTextBox.Text)
'Calculate values for sale.
ExtendedPriceDecimal = QuantityInteger * PriceDecimal
DiscountDecimal = Decimal.Round( _
(ExtendedPriceDecimal * DISCOUNT_RATE_Decimal), 1)
DiscountedPriceDecimal = ExtendedPriceDecilmal - DiscountDecimal
 
'Calculate summary values.
QuantitySumInteger += QuantityInteger
DiscountSumDecimal += DiscountDecimal
SaleCountInteger += 1
AverageDiscountDecimal = DiscountSumDecimal / SaleCountInteger
 
'Format and display answer for the sale
ExtendedPriceTextBox.Text = ExtendedPriceDecimal.ToString("C")
DiscountTextBox.Text = DiscountDecimal.ToString("N")
DiscountedTextBox.Text = DiscountedPriceDecimal.ToString("C")
'Format and display summary values.
QuantitySumTextBox.Text = QuantitySumInteger.ToString()
DiscountTextBox.Text = DiscountedSumDecimal.ToString("C")
AverageDiscountTextBox.Text = AverageDescountDecimal.ToString("C")
 
Catch PriceException As FormatException
'Handle a price exception
MessageBox.Show("Price must be numeric.", "Data Entry Error", MessageBoxButtons.OK, MessageBoxIcon.Exclamation)
With PriceTextBox
.Focus()
.SelectAll()
End With
End Try
Try
Catch QuantityException As FormatException
'Handle a quantity exception.
MessageBox.Show("Quantity must be numeric. ", "Data Entry Error", MessageBoxButtons.OK, MessageBoxIcon.Exclamation)
With QuantityTextBox
.Focus()
.SelectAll()
End With
End Try
End Sub

Thanks

[tlhintoq]

TIP: When you first created your question you were asked to wrap your code with [code] tags.

It really does help a bunch. Look how much easier it is to read now that someone has done it for you. Its the button with a '#' on it. More on tags. They're cool. Check'em out.

[tlhintoq]

If you put a breakpoint at line 3 and walk through the code line by line, I'll bet it does run... then you get an error... then bail out of the function. Right?

[MrMancunian]

Did you do what tlhintoq told you to do? I think you just reposted your code without trying...

Steven

[shanehenery]

Hi

I have put in a breakpoint in line 3
then when I debug the hole program doesn't work
I had to end the program

[MrMancunian]

Any error message?

[shanehenery]

Hi
Once I debug it gives me a message
( A first chance exception of type 'System.FormatException' occurred in mscorlib.dll )


then I add my numbers to calculate
the red dot of the breakpoint gets that yellow arrow on it and the code turns yellow
after I click calculate then there is a message telling me
(not Responding)
then I need to end the program

[tlhintoq]

I'm going to assume this is your very first program in Visual Studio.
Visual Studio is a powerful program. You really should take the time to learn how to use it and understand it. There are many good books on learning Visual Studio *before* you try to write code with it.

It's kind of like learning to use the controls of a car (gas, brake, steering) before asking for directions on how to drive from New York to Los Angeles.

the red dot of the breakpoint gets that yellow arrow on it and the code turns yellow
after I click calculate then there is a message telling me
(not Responding)
then I need to end the program

Your program is 'not responding' because it is stopped on the breakpoint line. While it is stopped you can look at the 'Autos' and 'Locals' pallets to see the values of your variables. You walk through your code one line at a time by pressing the F-10 function key. There are other options as well, listed in the Debug menu, such as F11 to step into a method you are calling.

Once I debug it gives me a message
( A first chance exception of type 'System.FormatException' occurred in mscorlib.dll )

Someplace where you are trying to format one of your numbers is failing.

You probably also want to start with a smaller amount of code and work up to something as large as what you are doing here. Start with just 1 calculation and 1 text box. Work out what is wrong with the formatting calls you are making. *THEN* you can apply the correct technique to a second calculation, then a third, and so on.

[shanehenery]

Hi

Yes this is my 3rd project
I have put in a breakpoint and went from line to line with F10
from this line

 Const DISCOUNT_RATE_Decimal As Decimal = 0.15D 

and it stops by this line

 Private Sub RnR_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load 

once it stoped then my project pops up and it gives me a message in a Immediate window

[message] A first chance exception of type 'System.FormatException' occurred in mscorlib.dll [/message]

wat can be wrong and how do i fix it
can you pleas help

[tlhintoq]

Const DISCOUNT_RATE_Decimal As Decimal = 0.15D 

I'm pretty sure you have to specify the 0.15 as a decimal with a lower case d not D

[shanehenery]

Hi

It is still not working

I cant change the

Const DISCOUNT_RATE_Decimal As Decimal = 0.15D

0.15D to a lower case d

It gos back to a D by defult

And I have declared

Const DISCOUNT_RATE_Decimal As Decimal = 0.15D

as a Decimal

[tlhintoq]

Do you have to supply the 'D' at all?
Can't you just say
Const DISCOUNT_RATE_Decimal As Decimal = 0.15

I can do that in C#

[shanehenery]

Hi

Yes , I can remove the 'D' but it doesn't make to program to calculate
it is still not working

[mshmyob]

Am I not seeing something here???

I don't event see the CONST line that you indicated in your code or your RnR_Load sub code either.

Maybe I am missing something. This does not look like the code you are talking about.

Correct me if I am wrong.

cheers,

[shanehenery]

HI

This is the code I am using
It needs to calculate the amount of books you bye with its discount of 15%
nothing is calculating

Public Class Form1
 
'Declare module-level variables and constants
    Private QuantitySumInteger, SaleCountinteger As Integer
    Private DiscountSumDecimal, DiscountedPriceSumDecimal As Decimal
    Const DISCOUNT_RATE_Decimal As Decimal = 0.15D
 
    Private Sub CalculateButton_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles CalculateButton.Click
        'Calculate the price and discount
 
        Dim QuantityInteger As Integer
        Dim PriceDecimal, ExtendedPriceDecimal, DiscountDecimal, DiscountedPriceDecimal, AverageDiscountDecimal, _
         DISCOUNT_RATE_Decimal, ExtendedPriceDecilmal, SaleCountInteger, _
           DiscountedSumDecimal, AverageDescountDecimal As Decimal
        Try
            'Convert quantity to numeric variable
            QuantityInteger = Integer.Parse(QuantityTextBox.Text)
        Catch ex As Exception
        End Try
 
 
Try
            'Convertprice if quantity was successful.
 
            PriceDecimal = Decimal.Parse(PriceTextBox.Text)
            'Calculate values for sale.
            ExtendedPriceDecimal = QuantityInteger * PriceDecimal
            DiscountDecimal = Decimal.Round( _
            (ExtendedPriceDecimal * DISCOUNT_RATE_Decimal), 2)
            DiscountedPriceDecimal = ExtendedPriceDecilmal - DiscountDecimal
 
 
            'Calculate summary values.
            QuantitySumInteger += QuantityInteger
            DiscountSumDecimal += DiscountDecimal
            SaleCountInteger += 1
            AverageDiscountDecimal = DiscountSumDecimal / SaleCountInteger
 
 
            'Format and display answer for the sale
            ExtendedPriceTextBox.Text = ExtendedPriceDecimal.ToString("C")
            DiscountTextBox.Text = DiscountDecimal.ToString("N")
            DiscountedPriceTextBox.Text = DiscountedPriceDecimal.ToString("C")
 
            'Format and display summary values.
 
            QuantitySumTextBox.Text = QuantitySumInteger.ToString()
            DiscountTextBox.Text = DiscountedSumDecimal.ToString("C")
            AverageDiscountTextBox.Text = AverageDescountDecimal.ToString("C")
 
 
        Catch PriceException As FormatException
            'Handle a price exception
            MessageBox.Show("Price must be numeric.", "Data Entry Error", MessageBoxButtons.OK, MessageBoxIcon.Exclamation)
            With PriceTextBox
                .Focus()
                .SelectAll()
            End With
        End Try
        Try
        Catch QuantityException As FormatException
            'Handle a quantity  exception.
            MessageBox.Show("Quantity must be numeric. ", "Data Entry Error", MessageBoxButtons.OK, MessageBoxIcon.Exclamation)
            With QuantityTextBox
                .Focus()
                .SelectAll()
            End With
        End Try
    End Sub
 

[tlhintoq]

Your entire process is in a single Try/Catch block. That means if any single part fails, the entire things fails. You should break this up so that each individual calculation is in it's own try/catch.

[message] A first chance exception of type 'System.FormatException' occurred in mscorlib.dll [/message]
You know you have a format exception. So stop trying to integrate formating in your calls.

DiscountTextBox.Text = DiscountedSumDecimal.ToString("C")

Take out all your "C" and "N" formatters. Just throw whatever string is made into the textbox to at least see if your calculations are working. *AFTER IT ALL CALCULATING* then you can format just one line and run it again. If that works, format one more line.

I have put in a breakpoint and went from line to line with F10
from this line
Expand|Select|Wrap|Line Numbers
Const DISCOUNT_RATE_Decimal As Decimal = 0.15D

If you are only using F10 then you are skipping over the actual calculation part, for line-by-line stepping.

Since you want to debug the method that takes place after you click the [Calculate] button, that is where you should put the breakpoint: Inside the Calculate button handler.

Dim QuantityInteger As Integer

Line 11 from your sample above.
Now you can step through the method causing trouble until you find the bug.

[shanehenery]

Hi

I have added the individual Try/Catch block of each calculation
and I have removed the "C"and"N"
it is still not calculating at all

only thing it is calculating is the "QuantityTextBox"+ "PriceTextBox" ="ExtendedPriceTextBox"

[mshmyob]

I am a little confused again.

I now see where you are declaring DISCOUNT_RATE_Decimal (line 6) as a constant, but then later under your button code you dimension it again (line 13). I have never done that but usually when you dimension a variable it resets the value of the variable to the default value (which would be 0 in this case).

Could it be that by dimensioning your variable AFTER you have set it as a constant that it is no longer a constant and is proceeding through your code with a value of 0 instead of .15 ?

cheers,

[shanehenery]

Hi

ok I left DISCOUNT_RATE_Decimal as a Const
and deleted the one that was extra in dimensioning(line 13)
it is calculating the dscount as 0.15D thats fine now
but it is showing "0.00" in the DiscountTextBox
when I click calculate.

but the rest of the calculation is not working
be cos from ther I need to calculate the summary af the Total Discount , Total Discount Amount and Average Discount

[shanehenery]

Hi

and it is giving me this message "A first chance exception of type 'System.DivideByZeroException' occurred in mscorlib.dll" and "A first chance exception of type 'System.FormatException' occurred in mscorlib.dll"

where can I look for the code so then I can fix it

[mshmyob]

@shanehenery
OK you are still confusing me with your responses.

Fixing your dimensioning fixed your discount problem.

Now you say the DiscountTextBox displays 0.00 - does this mean DiscountedSumDecimal gives the proper answer but is not being displayed on your form properly?

What does it mean when you say the rest of the calculation is not working?

Maybe the other people are mind readers but I failed that course.

Can you please be very very specific and indicate what the variables are when the system gives the error.

Also as previously indicated remove ALL error trapping and ALL formatting and work with just the bare bones code needed to get the result you want. After that is working you can throw back in formatting and trapping.

cheers,

[tlhintoq]

Here's what I'm hearing at this point...
"The entire thing doesn't work - some one tell me what's wrong with it."

You need to debug your program one line at a time. You need to use the tools Visual Studio provides. The 'Locals' and 'Autos' pallets will show you the values of your variables at each line.

Do a calculation, step one line
Do a calculation, step one line
As soon as the answer to one calculation is wrong - stop debugging and fix that one calculation.
Then start over
Do a calculation, step one line
Do a calculation, step one line

Eventually you will fix each calculation so they all work.

This is how basic debugging works. One line at a time. It's slow and tedieous: Welcome to programming!

This is a very simple need. It is nothing more complex than 7th grade math. Don't make more of it than it really is. It's easy to get frustrated and see the entire program as one big problem. Don't get caught in that trap. Break it down into little pieces. One line at a time. Don't try to solve the entire application. Just solve one line. Then solve another line.

[barnaba]

have you found the solution?

[shanehenery]

Hi

I have a problem in my coding I will like to deduct 15% from my RentalAmountTextBox to be displayed in my
AmountDueTextBox

AmountDueTextBox.Text = RentalAmountDecimal - 0.1

then in my AmountDueTextBox it only displays -0.1
it is not doing the calculation
an you pleas help

Public Class VideoBonanza
    'Declare module-level variables and constants.
 
    Private TotalSumInteger, MemberInteger, SaleCountInteger As Integer
    Private TotalRentalSumDecimal As Decimal
    Const Discount_Rate_Decimal As Decimal = 0.1D
 
    Private Sub VideoBonanza_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
 
    End Sub
 
    Private Sub CalculateButton_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles CalculateButton.Click
        'Calculate the rental amounts 
 
        Dim QuantityInteger As Integer
        Dim RentalAmountDecimal, DiscountDecimal, AmountDueDecimal As Decimal
 
        Try
            'Convert Quantity to numeric variable.
            QuantityInteger = Integer.Parse(QuantityTextBox.Text)
            AmountDueTextBox.Text = (RentalAmountDecimal - DiscountDecimal).ToString("C")
            DiscountDecimal = Decimal.Round(RentalAmountDecimal * Discount_Rate_Decimal, 2)
            AmountDueDecimal = RentalAmountDecimal - DiscountDecimal
            RentalAmountTextBox.Text = RentalAmountDecimal.ToString("C")
            AmountDueTextBox.Text = AmountDueDecimal.ToString("C")
 
        Catch Member As Exception
            'Handle a member exception
            MessageBox.Show("Enter Member Number.", "Data Entry Error", MessageBoxButtons.OK, MessageBoxIcon.Exclamation)
            With MemberTextBox
                .Focus()
                .SelectAll()
            End With
        End Try
        Try
            'Calculate the summary
            TotalSumInteger += MemberInteger
            MemberInteger += 1
            'Calculate the total Rentals of the quantity videos rented
            TotalRentalSumDecimal += QuantityInteger.ToString()
            DiscountTextBox.Text = RentalAmountDecimal - 0.1
            AmountDueTextBox.Text = RentalAmountDecimal - 0.1
 
        Catch ex As Exception
        End Try
 
        Try
            'Calculate the rentals amount
            RentalAmountTextBox.Text = (QuantityInteger * 1.8).ToString("C")
 
            'Calculate the total Rentals of the quantity videos rented
            TotalRentalSumTextBox.Text = TotalRentalSumDecimal
 
            TotalSumTextBox.Text = MemberInteger.ToString()
 
        Catch ex As Exception
 
        End Try
 
    End Sub
 

[tlhintoq]

Shane:
I once asked you if this was your first project and you said it was your third.
Looking at your posts I see you started 3 threads. *ALL* of them are for the inability to calculate in a project, with only slight differences.

Please do not start multiple threads for the same issue. It divides efforts to help you.

It is becoming very clear that you need to start on a smaller scale. All three of your projects are failing for the same reason: You are trying to create programs that must go through an entire process of multiple calculations before you have worked out how to do a single calculation.

In addition, you need to take some time to learn your way around Visual Studio itself.

Microsoft Press does some good "Learn to Program in {Language}" books that are designed to teach you Visual Studio while building up your coding skills. I HIGHLY recommend dropping by the bookstore or library.

At the very least, you need to reduce the complexity of your calculation process. You need to learn how to take the value in A, add it to B and display it in C - before trying to do 10 times that all in one method. As I have mentioned before, having the entire process in one method means the method fails as soon as you have one back step.