WPF - 在卸载后销毁页面

Question

在 WPF 应用中，我们有时需要创建一个新选项卡，其中包含框架中的页面。

打开页面（初始化一次）后，它似乎仍保留在导航历史记录中，并尝试加载当时可能不相关的数据。

我已经尝试了无数的方法，包括NavigationService.RemoveBackEntry，但它仍然存在：-（

这是如何打开选项卡/页面的示例

 Private Sub CashFlow_Edit(sender As Object, e As RoutedEventArgs)
    Try
        Dim DGV As DGVx = ReportsCashFlow_Grid.FindName("CashFlow_DGV")
        e.Handled = True
        IsNewRecord = False
        If DGV.SelectedItems.Count = 1 Then
            Dim row As System.Data.DataRowView = DGV.SelectedItems(0)
            Form_ID = row("ID")
            Dim vName As String = row("Name")
            Dim vTab As STC_Tabx = Application.Current.MainWindow.FindName(TabName)
            Dim TabControl As STCx = Application.Current.MainWindow.FindName("AccountingReports_TabControl")
            If Not vTab Is Nothing Then
                vTab.Close()
            End If
            Dim MCFrame As New Frame
            Dim MCTab As New STC_Tabx
            With MCTab
                .Name = TabName
                .Header = " " & vName & " "
                .ImageSource = ReturnImageAsString("Edit.png", 16)
                .CloseButtonVisibility = DevComponents.WpfEditors.eTabCloseButtonVisibility.Visible
                .TabToolTip = "View or edit the " & vName & " template"
                .Content = MCFrame
            End With
            RemoveHandler MCTab.Closing, AddressOf TabControl_TabClosing
            AddHandler MCTab.Closing, AddressOf TabControl_TabClosing
            Dim vGrid As Grid = Application.Current.MainWindow.FindName("MainGrid_Accounting")
            RegisterControl(vGrid, MCTab)
            TabControl.Items.Add(MCTab)
            Dim MCPage As New ReportCashFlow_Page
            MCFrame.NavigationService.Navigate(MCPage)
            LoadedTabs(TabName)
            MCTab.IsSelected = True

        End If
    Catch ex As Exception
        EmailError(ex)
    End Try
End Sub

Answer 1

要删除所有后退条目，请执行以下操作：

while(NavigationService.CanGoBack)
{
    NavigationService.RemoveBackEntry();
}

Answer 2

这不是我想要的干净代码，但它有效 - 创建一个全局布尔值 - 当打开选项卡/页面的 sub 被调用时，它设置为 true，并且加载事件将仅在这是真的时运行加载代码 - 它最后设置为 false。

Private Sub ReportCashFlow_Page_Loaded(sender As Object, e As RoutedEventArgs) Handles Me.Loaded
    Try

        If IsNewTab = False Then
            Exit Sub
        End If
 'Run all the loading code here

  Catch ex As Exception
        EmailError(ex)
    Finally
        IsNewTab = False
        Dispatcher.CurrentDispatcher.BeginInvoke(DispatcherPriority.Background, CType(Sub() CashFlow_LoadBudget(), SendOrPostCallback), Nothing)
        Dispatcher.CurrentDispatcher.BeginInvoke(DispatcherPriority.Background, CType(Sub() ToggleReserve(), SendOrPostCallback), Nothing)
    End Try
End Sub