Visual Basic代码 - 无法显示Total。 VB新手

Question

我必须编写一个计算餐饮公司成本的程序。我有那个部分，但是最让我感到难过的是我在显示总数时遇到了麻烦。令我感到困惑的是，我必须制作一个摘要按钮，将所有内容从之前的计算中添加到总计中，并将其显示在消息框中。显示和计算并不是我的问题，但是要计算数据是。 谢谢

这是代码。

Const decPRIME_RIB As Decimal = 25.95D
Const decCHICKEN As Decimal = 18.95D
Const decPASTA As Decimal = 12.95D
Const decOPEN_BAR As Decimal = 25D
Const decWINE As Decimal = 8D
Const decBEER As Decimal = 10D

'Declare module-level variables for summary information.
Private TotalDollar As Decimal
Private AmountDue As Decimal
Private SubTotalDecimal As Decimal
Private TotalDecimal As Decimal
Private Guest As Integer
Private EventCountInteger As Integer

Private Sub CalcBtn_Click(sender As Object, e As EventArgs) Handles CalcBtn.Click
    ' Calculate and display the current amounts and add to totals.
    Dim FoodChoiceDecimal As Decimal
    Dim OpenBarDecimal As Decimal
    Dim WineDecimal As Decimal
    Dim DrinksDecimal As Decimal

    ' Find the price.
    If PrimeRB.Checked Then
        FoodChoiceDecimal = decPRIME_RIB
    ElseIf ChickRB.Checked Then
        FoodChoiceDecimal = decCHICKEN
    ElseIf PastaRB.Checked Then
        FoodChoiceDecimal = decPASTA
    End If

    If OpenCB.Checked Then
        OpenBarDecimal = decOPEN_BAR
    End If
    If WineCB.Checked Then
        WineDecimal = decWINE
    End If

    'Multiply price by number of guest and drink selection.
    Try
        DrinksDecimal = (OpenBarDecimal + WineDecimal)
        AmountDue = (FoodChoiceDecimal + DrinksDecimal) * Guest


        ' display totals.
        TotalLbl.Text = TotalLbl.ToString("C")

        ' Allow change for new event.
        OpenCB.Enabled = False
        WineCB.Enabled = False
        ClearBtn.Enabled = True
        SummaryBtn.Enabled = True

    Catch NumberOfGuestsException As FormatException
        MessageBox.Show("Number of Guests must be Numeric", _
        "Data entry Error", MessageBoxButtons.OK, _
        MessageBoxIcon.Information)



    End Try
End Sub


Private Sub SummaryBtn_Click(sender As Object, e As EventArgs) Handles SummaryBtn.Click
    ' Calculate total dollar amounts and number of events.

    Dim MessageString As String
    If EventCountInteger > 0 Then
        ' Calculate the summary sales totals.
        TotalDollar += AmountDue

        'Concatenate the message string.
        MessageString = "Number of Events:" & EventCountInteger.ToString() _
        & Environment.NewLine & Environment.NewLine _
        & "Total Sales: " & TotalDollar.ToString("C")
        MessageBox.Show(MessageString, "Sales Summary", _
        MessageBoxButtons.OK, MessageBoxIcon.Information)
    End If