问我需要将textbox.text转换为十进制值，以便汇总总数并显示在消息框中。使用vb 2010

EN

'Declare Item Structure.
Structure Item
    Dim upcString As String
    Dim nameString As String
    Dim descriptionString As String
    Dim weightString As String
    Dim priceDecimal As Decimal
End Structure

'Declare the ItemPrices Structure
Public Structure ItemPrices
    Dim itemdescriptionString As String
    Dim itempriceDecimal As Decimal
    Dim itemweightDecimal As Decimal
    Dim itemupcInteger As Integer
End Structure

Public Class lab7Form
    Private price1Decimal As Decimal
    Private subTotalDecimal As Decimal
    Private grandTotalDecimal As Decimal
    Private totalDecimal As Decimal
    Private totalItemsInteger As Integer
    Private MessageString As String
    Private totalWeightDecimal As Decimal

    Dim myItem As Item
    Private ItemPricesArray(3) As ItemPrices

    Private Sub exitButton_Click(sender As System.Object, e As System.EventArgs) Handles exitButton.Click
        If MsgBox("Click Yes to Exit, Click No to Cancel", MsgBoxStyle.YesNo, "You Decide") = MsgBoxResult.Yes Then
            Me.Close()
        End If
    End Sub

    Private Sub clearButton_Click(sender As System.Object, e As System.EventArgs) Handles clearButton.Click
        'Clear the textbox values.
        upcTextBox.Text = ""
        descriptionTextBox.Text = ""
        weightTextBox.Text = ""
        priceTextBox.Text = ""
    End Sub

    Private Sub lab7Form_Load(sender As System.Object, e As System.EventArgs) Handles MyBase.Load
        'Load my itemsListbox with the items for the user.
        itemsListBox.Items.Add("Notebook PC")
        itemsListBox.Items.Add("Deskjet Printer")
        itemsListBox.Items.Add("Color Ink Cartridge")
        itemsListBox.Items.Add("Black Ink Cartridge")

        'Load the ItemPricesArray values. 
        ItemPricesArray(0).itemdescriptionString = "Notebook PC"
        ItemPricesArray(1).itemdescriptionString = "Deskjet Printer"
        ItemPricesArray(2).itemdescriptionString = "Color Ink Cartridge"
        ItemPricesArray(3).itemdescriptionString = "Black Ink Cartridge"

        ItemPricesArray(0).itempriceDecimal = 1500D
        ItemPricesArray(1).itempriceDecimal = 430D
        ItemPricesArray(2).itempriceDecimal = 11D
        ItemPricesArray(3).itempriceDecimal = 10D

        ItemPricesArray(0).itemweightDecimal = 7D
        ItemPricesArray(1).itemweightDecimal = 16D
        ItemPricesArray(2).itemweightDecimal = 0.5D
        ItemPricesArray(3).itemweightDecimal = 0.5D

        ItemPricesArray(0).itemupcInteger = 111111111
        ItemPricesArray(1).itemupcInteger = 222222222
        ItemPricesArray(2).itemupcInteger = 333333333
        ItemPricesArray(3).itemupcInteger = 444444444
    End Sub

    Private Sub itemsListBox_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles itemsListBox.SelectedIndexChanged
        descriptionTextBox.Text = itemsListBox.Text
        'I am using a table lookup   Do/Loop here.
        Dim myBoolean As Boolean        'True = I found an items price.
        Dim indexInteger As Integer = 0
        Do Until myBoolean Or indexInteger > 3
            With Me
                If .descriptionTextBox.Text = ItemPricesArray(indexInteger).itemdescriptionString Then
                    .priceTextBox.Text = ItemPricesArray(indexInteger).itempriceDecimal.ToString("C")
                    .weightTextBox.Text = ItemPricesArray(indexInteger).itemweightDecimal.ToString()
                    .upcTextBox.Text = ItemPricesArray(indexInteger).itemupcInteger.ToString()
                    myBoolean = True
                Else
                    indexInteger += 1
                End If
            End With
        Loop
    End Sub

    Private Sub purchaseButton_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles purchaseButton.Click
         Dim DecNumber1 As Decimal
        'Parse Numbers 
        DecNumber1 = Decimal.Parse(priceTextBox.Text)

        If purchaseButton.Enabled And priceTextBox.Text <> "" Then
            'Calculate the quantities
            totalItemsInteger += 1  'I can't figure out how to total up the weights and prices when they are both local variables.
            subTotalDecimal += DecNumber1
            totalWeightDecimal += 1

            'From Page 172 Put together what you want to appear in message boxes
            Dim MessageString As String
            Dim totalString As String
            Dim numberOfItemsString As String
            Dim weightOfItemsString As String

            numberOfItemsString = totalItemsInteger.ToString()
            totalString = subTotalDecimal.ToString("C")
            weightOfItemsString = totalWeightDecimal.ToString("N")

            MessageString = "Total Items : " & numberOfItemsString &
                Environment.NewLine & "Total Weight: " & weightOfItemsString &
                Environment.NewLine & "Subtotal: " & totalString

            'Display the message box
            MessageBox.Show(MessageString, "Items Purchased", MessageBoxButtons.OKCancel)
        End If
    End Sub

    Private Sub totalButton_Click(sender As System.Object, e As System.EventArgs) Handles totalButton.Click
        Dim numberofOrdersString As String
        If totalButton.Enabled Then
            numberofOrdersString = "Number of Orders:  " & totalItemsInteger.ToString()
            MessageString = "Total Sales:  " & grandTotalDecimal.ToString("C")

            'Display the message box
            MessageBox.Show(MessageString, "Items Purchased", MessageBoxButtons.OKCancel)
        End If
    End Sub
End Class