An Error with a program

Jblake00 · Oct 1, 2003

Ok here is my code.

Dim sum As Decimal
sum = CDbl(TxtListNumBooks.Text) * 0.1 * CDbl(TxtListNumDaysLate.Text)

LblShowFines.Text = "Your total fine is: " & CStr(FormatCurrency(sum))
LblShowFines.BorderStyle = BorderStyle.FixedSingle

What this does is make a simple program that calculates a fine.
It seems to work fine as long as I type an input into the test boxs.
I can even put 0 and 0 in them.
The problem occurs when I don't put an input into them.
Any suggestions.??

Btw I need a little input it making another form popup if fine = more than so many dollars.

mutant · Oct 1, 2003

You can check if the Text of the Textboxes is empty or not and if it is then stop the execution of the calculation.

Visual Basic:

If TextBoxObject.Text = '" Then
'tell the user to input something
End If

Jblake00 · Oct 1, 2003

Not exactly what I was looking for but thanks.
Im sorry I didn't clarify what I wanted my result to be the first time.
But this is what I what it to do.
If no input is added when the Button calculate fines is pushed I want it to display " your fine is: $0.00

Jblake00 · Oct 1, 2003

Visual Basic:

ublic Class Form1
    Inherits System.Windows.Forms.Form

#Region " Windows Form Designer generated code "

    Public Sub New()
        MyBase.New()

        'This call is required by the Windows Form Designer.
        InitializeComponent()

        'Add any initialization after the InitializeComponent() call

    End Sub

    'Form overrides dispose to clean up the component list.
    Protected Overloads Overrides Sub Dispose(ByVal disposing As Boolean)
        If disposing Then
            If Not (components Is Nothing) Then
                components.Dispose()
            End If
        End If
        MyBase.Dispose(disposing)
    End Sub

    'Required by the Windows Form Designer
    Private components As System.ComponentModel.IContainer

    'NOTE: The following procedure is required by the Windows Form Designer
    'It can be modified using the Windows Form Designer.  
    'Do not modify it using the code editor.
    Friend WithEvents LblTypeNumBooks As System.Windows.Forms.Label
    Friend WithEvents LblTypeNumDaysLate As System.Windows.Forms.Label
    Friend WithEvents LblShowFines As System.Windows.Forms.Label
    Friend WithEvents LlbThankYou As System.Windows.Forms.Label
    Friend WithEvents TxtListNumBooks As System.Windows.Forms.TextBox
    Friend WithEvents TxtListNumDaysLate As System.Windows.Forms.TextBox
    Friend WithEvents BtnCalulateFines As System.Windows.Forms.Button
    Friend WithEvents BtnExit As System.Windows.Forms.Button
    <System.Diagnostics.DebuggerStepThrough()> Private Sub InitializeComponent()
        Me.LblTypeNumBooks = New System.Windows.Forms.Label()
        Me.LblTypeNumDaysLate = New System.Windows.Forms.Label()
        Me.LblShowFines = New System.Windows.Forms.Label()
        Me.LlbThankYou = New System.Windows.Forms.Label()
        Me.TxtListNumBooks = New System.Windows.Forms.TextBox()
        Me.TxtListNumDaysLate = New System.Windows.Forms.TextBox()
        Me.BtnCalulateFines = New System.Windows.Forms.Button()
        Me.BtnExit = New System.Windows.Forms.Button()
        Me.SuspendLayout()
        '
        'LblTypeNumBooks
        '
        Me.LblTypeNumBooks.Font = New System.Drawing.Font("Microsoft Sans Serif", 8.25!, System.Drawing.FontStyle.Bold, System.Drawing.GraphicsUnit.Point, CType(0, Byte))
        Me.LblTypeNumBooks.ForeColor = System.Drawing.Color.Blue
        Me.LblTypeNumBooks.Location = New System.Drawing.Point(8, 40)
        Me.LblTypeNumBooks.Name = "LblTypeNumBooks"
        Me.LblTypeNumBooks.Size = New System.Drawing.Size(112, 32)
        Me.LblTypeNumBooks.TabIndex = 0
        Me.LblTypeNumBooks.Text = "Type the number of books here ----->"
        '
        'LblTypeNumDaysLate
        '
        Me.LblTypeNumDaysLate.Font = New System.Drawing.Font("Microsoft Sans Serif", 8.25!, System.Drawing.FontStyle.Bold, System.Drawing.GraphicsUnit.Point, CType(0, Byte))
        Me.LblTypeNumDaysLate.ForeColor = System.Drawing.Color.Blue
        Me.LblTypeNumDaysLate.Location = New System.Drawing.Point(8, 88)
        Me.LblTypeNumDaysLate.Name = "LblTypeNumDaysLate"
        Me.LblTypeNumDaysLate.Size = New System.Drawing.Size(112, 32)
        Me.LblTypeNumDaysLate.TabIndex = 1
        Me.LblTypeNumDaysLate.Text = "Type the number of days late ------>"
        '
        'LblShowFines
        '
        Me.LblShowFines.Font = New System.Drawing.Font("Microsoft Sans Serif", 10.0!, System.Drawing.FontStyle.Bold, System.Drawing.GraphicsUnit.Point, CType(0, Byte))
        Me.LblShowFines.Location = New System.Drawing.Point(336, 56)
        Me.LblShowFines.Name = "LblShowFines"
        Me.LblShowFines.Size = New System.Drawing.Size(144, 32)
        Me.LblShowFines.TabIndex = 2
        Me.LblShowFines.TextAlign = System.Drawing.ContentAlignment.MiddleCenter
        '
        'LlbThankYou
        '
        Me.LlbThankYou.Font = New System.Drawing.Font("Microsoft Sans Serif", 12.0!, (System.Drawing.FontStyle.Bold Or System.Drawing.FontStyle.Italic), System.Drawing.GraphicsUnit.Point, CType(0, Byte))
        Me.LlbThankYou.ForeColor = System.Drawing.Color.Blue
        Me.LlbThankYou.Location = New System.Drawing.Point(136, 136)
        Me.LlbThankYou.Name = "LlbThankYou"
        Me.LlbThankYou.Size = New System.Drawing.Size(280, 23)
        Me.LlbThankYou.TabIndex = 3
        Me.LlbThankYou.Text = "Thanks for your prompt payment"
        Me.LlbThankYou.TextAlign = System.Drawing.ContentAlignment.MiddleCenter
        '
        'TxtListNumBooks
        '
        Me.TxtListNumBooks.BorderStyle = System.Windows.Forms.BorderStyle.None
        Me.TxtListNumBooks.Font = New System.Drawing.Font("Microsoft Sans Serif", 12.0!, System.Drawing.FontStyle.Bold, System.Drawing.GraphicsUnit.Point, CType(0, Byte))
        Me.TxtListNumBooks.Location = New System.Drawing.Point(144, 40)
        Me.TxtListNumBooks.Multiline = True
        Me.TxtListNumBooks.Name = "TxtListNumBooks"
        Me.TxtListNumBooks.Size = New System.Drawing.Size(72, 20)
        Me.TxtListNumBooks.TabIndex = 4
        Me.TxtListNumBooks.Text = ""
        Me.TxtListNumBooks.TextAlign = System.Windows.Forms.HorizontalAlignment.Center
        '
        'TxtListNumDaysLate
        '
        Me.TxtListNumDaysLate.AllowDrop = True
        Me.TxtListNumDaysLate.BorderStyle = System.Windows.Forms.BorderStyle.None
        Me.TxtListNumDaysLate.Font = New System.Drawing.Font("Microsoft Sans Serif", 12.0!, System.Drawing.FontStyle.Bold, System.Drawing.GraphicsUnit.Point, CType(0, Byte))
        Me.TxtListNumDaysLate.Location = New System.Drawing.Point(144, 88)
        Me.TxtListNumDaysLate.Multiline = True
        Me.TxtListNumDaysLate.Name = "TxtListNumDaysLate"
        Me.TxtListNumDaysLate.Size = New System.Drawing.Size(72, 20)
        Me.TxtListNumDaysLate.TabIndex = 5
        Me.TxtListNumDaysLate.Text = ""
        Me.TxtListNumDaysLate.TextAlign = System.Windows.Forms.HorizontalAlignment.Center
        '
        'BtnCalulateFines
        '
        Me.BtnCalulateFines.Font = New System.Drawing.Font("Microsoft Sans Serif", 8.25!, System.Drawing.FontStyle.Bold, System.Drawing.GraphicsUnit.Point, CType(0, Byte))
        Me.BtnCalulateFines.Location = New System.Drawing.Point(224, 56)
        Me.BtnCalulateFines.Name = "BtnCalulateFines"
        Me.BtnCalulateFines.Size = New System.Drawing.Size(104, 32)
        Me.BtnCalulateFines.TabIndex = 6
        Me.BtnCalulateFines.Text = "Calculate Fine"
        '
        'BtnExit
        '
        Me.BtnExit.Font = New System.Drawing.Font("Microsoft Sans Serif", 8.25!, System.Drawing.FontStyle.Bold, System.Drawing.GraphicsUnit.Point, CType(0, Byte))
        Me.BtnExit.Location = New System.Drawing.Point(392, 168)
        Me.BtnExit.Name = "BtnExit"
        Me.BtnExit.Size = New System.Drawing.Size(56, 23)
        Me.BtnExit.TabIndex = 7
        Me.BtnExit.Text = "E&xit"
        '
        'Form1
        '
        Me.AutoScaleBaseSize = New System.Drawing.Size(5, 13)
        Me.BackColor = System.Drawing.Color.FromArgb(CType(128, Byte), CType(255, Byte), CType(128, Byte))
        Me.ClientSize = New System.Drawing.Size(488, 198)
        Me.Controls.AddRange(New System.Windows.Forms.Control() {Me.BtnExit, Me.BtnCalulateFines, Me.TxtListNumDaysLate, Me.TxtListNumBooks, Me.LlbThankYou, Me.LblShowFines, Me.LblTypeNumDaysLate, Me.LblTypeNumBooks})
        Me.Name = "Form1"
        Me.Text = "Library Fine Calulation"
        Me.ResumeLayout(False)

    End Sub

#End Region

    Private Sub BtnExit_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles BtnExit.Click
        End

    End Sub

    Private Sub LblShowFines_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles LblShowFines.Click


    End Sub

    Private Sub BtnCalulateFines_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles BtnCalulateFines.Click


        Dim sum As Double

        sum = CDbl(TxtListNumBooks.Text) * 0.1 * CDbl(TxtListNumDaysLate.Text)

        LblShowFines.Text = "Your total fine is:   " & CStr(FormatCurrency(sum))
        LblShowFines.BorderStyle = BorderStyle.FixedSingle


    End Sub

    Private Sub TxtListNumBooks_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles TxtListNumBooks.TextChanged
        TxtListNumBooks.TextAlign = HorizontalAlignment.Center

    End Sub

    Private Sub TxtListNumDaysLate_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles TxtListNumDaysLate.TextChanged
        TxtListNumDaysLate.TextAlign = HorizontalAlignment.Center

    End Sub

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

    End Sub

    Private Sub LblTypeNumBooks_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles LblTypeNumBooks.Click

    End Sub
End Class

Jblake00 · Oct 1, 2003

Ok there is my whole code if some could please tell me what and were to add something to make it display "Your total fine is: $0.00 if there is no input in the text boxes.

wyrd · Oct 1, 2003

Visual Basic:

    Private Sub BtnCalulateFines_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles BtnCalulateFines.Click


        Dim sum As Double

        Try
           sum = CDbl(TxtListNumBooks.Text) * 0.1 * CDbl(TxtListNumDaysLate.Text)
        Catch ex As Exception
            sum = 0
        End Try

        LblShowFines.Text = "Your total fine is:   " & CStr(FormatCurrency(sum))
        LblShowFines.BorderStyle = BorderStyle.FixedSingle


    End Sub

Jblake00 · Oct 2, 2003

Thanks
That solves half of the problem at least. The program no longer crashes in the debug stage when the calculate fine button is pressed, however it does not display my message "Your total fine is: $0.00.....
I really need to figure out how to do that.
Thank again, I really appreciate all the help I have been getting from you people.
This is a learning experience for me. It mean allot more to me than just getting a good grade. Programing is something I have really wanted to learn for a long time. I want yall to know that I don't just come here looking to be told about how to do something before I make many attemps to solve the problem myself. I use my help and search features that come we VB.net and search the forums looking for an answer before I post. If the answer to my question has already been post before and I have overlooked it. A link to that post would be a fine way to answer my question.

Jblake00 · Oct 2, 2003

Oops that caused the program to display no results when I added to the code even when I had an input in the text boxes.
I replaced the code with it I wander if I should have added it under my code?

wyrd · Oct 2, 2003

Can you show us what you currently have in your BtnCalculateFines_Click event?

Jblake00 · Oct 2, 2003

Visual Basic:

Private Sub BtnCalulateFines_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles BtnCalulateFines.Click
        'Clayton I am have much problems with this code.
        'When I use this code it works fine as long as there is an input.
        'But when there is no input it brings up an exception form when I debug.
        'So I tryed this try It keeps the program from crashing but also,
        'gives no output when there is an input 
        REM Try
        Dim sum As Double

        sum = CDbl(TxtListNumBooks.Text) * 0.1 * CDbl(TxtListNumDaysLate.Text)
        REM Catch ex As Exception
        REM Dim sum As DialogResult

        REM sum = 0.0


        LblShowFines.Text = "Your total fine is:   " & CStr(FormatCurrency(sum))
        LblShowFines.BorderStyle = BorderStyle.FixedSingle

        REM End Try

    End Sub

    Private Sub TxtListNumBooks_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles TxtListNumBooks.TextChanged
        TxtListNumBooks.TextAlign = HorizontalAlignment.Center

    End Sub

Jblake00 · Oct 2, 2003

I am not sure I am going about this calculating proccess in the right way. So if someone knows a better method please inform me. In another words I could be possibly trying to use the wrong code all together.

Jblake00 · Oct 2, 2003

Ok I learned how to create a message box

Visual Basic:

MsgBox("Warning if your debt is not payed promptly, Then it will be turned over to the StrongArmCollectionAgency.", , "Consolation")

But here is my two troubles.

If there is no input in my text boxes the program pops up an
error dialog.

I only want the message box to popup if the amount of the fine = 25 dollars or more.
[/list=1]
Here is my code.

Visual Basic:

Private Sub BtnCalulateFines_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles BtnCalulateFines.Click
        'Clayton I am have much problems with this code.
        'When I use this code it works fine as long as there is an input.
        'But when there is no input it brings up an exception form when I debug.
        'So I tryed this try It keeps the program from crashing but also,
        'gives no output when there is an input 
        REM Try
        Dim sum As Double

        sum = CDbl(TxtListNumBooks.Text) * 0.1 * CDbl(TxtListNumDaysLate.Text)

        REM Catch ex As Exception
        REM Dim sum As DialogResult

        REM sum = 0.0

        LblShowFines.Text = "Your total fine is:   " & CStr(FormatCurrency(sum))
        LblShowFines.BorderStyle = BorderStyle.FixedSingle
        MsgBox("Warning if your debt is not payed promptly, Then it will be turned over to the StrongArmCollectionAgency.", , "Consolation")

        REM End Try

    End Sub

wyrd · Oct 2, 2003

Look again at the code I gave you above.

You could also consider using Double.Parse() instead of CDbl().

As for displaying an error when the fines are $25 or more, use an if statement.

Now that I keep reading this, it seems more and more like a class assignment (is it?). In this case, I don't want to help too much, as giving you the right answers would defeat the purpose of learning.

Jblake00 · Oct 2, 2003

The problem is solved.
Here is the solution.

Visual Basic:

    Private Sub BtnCalulateFines_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles BtnCalulateFines.Click
        REM this button is used to do all the calculations 
        Dim sum As Double
        If TxtListNumBooks.Text = "" Then
            TxtListNumBooks.Text = "0"
        End If
        If TxtListNumDaysLate.Text = "" Then
            TxtListNumDaysLate.Text = "0"
        End If
        sum = CDbl(TxtListNumBooks.Text) * 0.1 * CDbl(TxtListNumDaysLate.Text)
        LblShowFines.Text = "Your total fine is:   " & CStr(FormatCurrency(sum))
        LblShowFines.BorderStyle = BorderStyle.FixedSingle
        'This is the code used to make a popup message appear when the fine is more than $1.50
        If (sum > "1.5") Then

            MsgBox("Warning if your debt is not payed promptly, Then it will be turned over to the StrongArmCollectionAgency.", , "Consolation")
        End If
        If (sum < "1.49") Then


            LlbThankYou.Text = "Thanks for your prompt payment"

        End If
    End Sub

I think Mutant was telling me basically what to do but I could quite grasp it at the time. And you too are right wyrd, I need to do some further reading. And that thing about catching an exception is very interesting, although it wasn't quite what I was looking for. But it may help me with something later on.
Also as I said I try very hard to come up with the solution before I ask for help here.
But if I can not get help when I need it, then I will become discusted and that is not a good thing.
Thanks again for your input.

wyrd · Oct 3, 2003

Actually, the error checking I gave you is needed. Try entering a non-numeric value (ie; letters) into your TxtListNumBooks and see what happens.

Jblake00 · Oct 3, 2003

Ok I will try it later, but first I got to reveiw for a test on chapter 3.
Which I am hopeing to ace. Then I have to read on in the book an try to comprehend the idea behind the code you are giveing me.
I have seen an example similar to what you give me.

wyrd · Oct 3, 2003

Ah.. well if you haven't gotten to error checking yet then don't worry, you'll get there eventually.

An Error with a program

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