vb.net - 如何在VB中累加总和？
您需要一个全局变量或一个带有公共变量的类。您应该创建一个Transaction类来存储有关交易的数据，并可能创建一个类来Product存储有关产品的数据。你放什么取决于你，但我会从这样的事情开始：
Public Class Transaction
Private _productsList As List(of Product)
Private _transationNumber As Integer
'...more stuff...
'you'll want to remember what products are in your "cart" for the transaction
Public Property ProductsList As List(of Product)
'your get/set accessors
End Property
Public Property TransactionNumber As Integer
'your get/set accessors
End Property
Public Property TotalTransactionCost() As Double
Get
'this will sum of the prices of all of the products you have stored in your
'list of products for this transaction
Return _productsList.Sum(product => product.Price)
End Get
End Property
Public Sub New()
'...constructor stuff
End Sub
Public Sub AddProductToTransaction(byval product)
_productsList.Add(product)
End Sub
End Class
Public Class Product
Private _price As Double
Private _productName As String
Private _UPC As String
Public Property Price() As Double
'your get/set accessors
End Property
Public Property ProductName() As String
'your get/set accessors
End Property
Public UPC As String () As String
'your get/set accessors
End Property
Public Sub New()
'constructor stuff
End Sub
End Class
这些是帮助您入门的几个类 shell。如果您认真地制作产品，那么这是朝着正确方向迈出的一步。如果您要编写代码，请以正确的方式编写代码。
如果您只是在寻找一个快速而肮脏的解决方案，您可以声明一个全局变量并保持一个运行总和。只是不要忘记在开始新交易之前将其清除。
您需要执行以下操作：
Private TransactionCost As Double在所有方法之外的形式中。
同样，我会推荐第一种处理方式。您至少需要这两个类，并且对于真正的产品，它们肯定会更加充实。
我希望这有助于并回答您的问题。如果是这样，请给我点赞并接受答案。欢迎来到 SO。