Public Class CaseStudyCh3_Auto_Center

        'Declares commission rate @ 20%.
        Const CommissionRateDecimal As Decimal = 0.2D

        Private Sub CalculateButton_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles CalculateButton.Click

            'Declares variables used in calculation; Sales price, cost price, commission, and MessageString.
            Dim MessageString As String
            Dim SalesPriceDecimal, CostPriceDecimal, CommissionDecimal As Decimal

            Dim HaveValidInputs As Boolean

            HaveValidInputs = True

            'Confirms employee's name is entered
            If String.IsNullOrEmpty(EmployeeNameTextBox.Text) Then
                HaveValidInputs = False

                'Displays error if employee's name is omitted.
                MessageString = "Please enter employee's name."
                MessageBox.Show(MessageString, "Error, Will Robinson!", MessageBoxButtons.OK)
                With EmployeeNameTextBox
                    .Focus()
                    .SelectAll()
                End With
            End If

            If HaveValidInputs = True Then
                Try
                    SalesPriceDecimal = Decimal.Parse(SalesPriceTextBox.Text)
                Catch SalesPriceException As FormatException
                    HaveValidInputs = False

                    'Catches sales price exception if input is not formatted as a decimal value.
                    MessageString = "Please enter sales price as a decimal with no dollar signs."
                    MessageBox.Show(MessageString, "Error, Will Robinson!",
                                    MessageBoxButtons.OK)
                    With SalesPriceTextBox
                        .Focus()
                        .SelectAll()
                    End With
                End Try
            End If

            If HaveValidIputs = True Then
                Try
                    CostPriceDecimal = Decimal.Parse(CostPriceTextBox.Text)
                Catch CostPriceException As FormatException
                    HaveValidInputs = False

                    'Catches cost price exception if input is not formatted as a decimal.
                    MessageString = "Please enter cost price as a decimal with no dollar signs."
                    MessageBox.Show(MessageString, "Error, Will Robinson!", MessageBoxButtons.OK)
                    With CostPriceTextBox
                        .Focus()
                        .SelectAll()
                    End With
                End Try
            End If

            If HaveValidInputs = True Then
                'Calculates commission for employee.
                If SalesPriceDecimal > CostPriceDecimal Then
                    CommissionDecimal = CommissionRateDecimal * (SalesPriceDecimal - CostPriceDecimal)
                Else
                    CommissionDecimal = 0
                End If

                'Displays commission total in text field.
                CommissionTextBox.Text = CommissionDecimal.ToString("C")
            End If

        End Sub

        Private Sub ClearButton_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ClearButton.Click

            'Clears all fields for new entry.
            With EmployeeNameTextBox
                .Clear()
                .Focus()
            End With
            SalesPriceTextBox.Clear()
            CostPriceTextBox.Clear()
            CommissionTextBox.Clear()

        End Sub

        Private Sub PrintButton_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles PrintButton.Click

            'Prints the form; need that $$$BLINGBLING$$$!
            PrintForm1.PrintAction = Printing.PrintAction.PrintToPreview
            PrintForm1.Print()

        End Sub

        Private Sub ExitButton_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ExitButton.Click

            'Closes the program.
            Me.Close()

        End Sub
    End Class