vb.net - 通知对另一个类或对象的更改

Question

我在一个小修复中，我有一个如下的类(class)。

Public Class Bill
    Public prime As BillPrime
    Public items As System.Collections.ObjectModel.ObservableCollection(Of ItemDetails)
    Public status As New BillStatus
    Public Sub New()
        prime = New BillPrime
        items = New System.Collections.ObjectModel.ObservableCollection(Of ItemDetails)
        status = New BillStatus
    End Sub
End Class

如何更新 prime 中的某些 x 值当 ItemDetails 中的任何一个发生变化时 items 中的对象.

你能帮我解决一下吗？

Answer 1

尝试使用 BindingList(of T)相反，您可以监听更改事件:

Imports System.ComponentModel

Public Class Bill
  Public prime As BillPrime
  Public WithEvents items As BindingList(Of ItemDetails)
  Public status As New BillStatus
  Public Sub New()
    prime = New BillPrime
    items = New BindingList(Of ItemDetails)
    status = New BillStatus
  End Sub

  Public Sub items_ListChanged(ByVal sender As Object, ByVal e As ListChangedEventArgs)  Handles items.ListChanged
    prime.X = "something"
  End Sub
End Class

这需要你的类实现 INotifyPropertyChanged :

Public Class ItemDetails
  Implements INotifyPropertyChanged

  Public Event PropertyChanged(ByVal sender As Object, ByVal e As PropertyChangedEventArgs) Implements INotifyPropertyChanged.PropertyChanged

  Private _DetailOne As String

  Property DetailOne() As String
    Get
      Return _DetailOne
    End Get
    Set(ByVal value As String)
      _DetailOne = value
      RaiseEvent PropertyChanged(Me, New PropertyChangedEventArgs("DetailOne"))
    End Set
  End Property

End Class