所以我面对这个问题,我有2页,ViewAccount和MainPage。列表框(不同页面)上的NullReferenceException
在MainPage中有一个名为SavedAccountsLst的ListBox。问题是,在ViewAccount页面中,一旦我点击一个按钮,它会抛出一个NullReferenceException
。
这是我使用的ViewAccount代码:
Private Sub Delete_Account_Click(ByVal sender As Object, ByVal e As System.EventArgs)
Dim Storage As IsolatedStorageFile = IsolatedStorageFile.GetUserStoreForApplication()
Storage.DeleteFile("SafeLockPLUS/SavedAccounts/" & PageTitle.Text)
MessageBox.Show(PageTitle.Text & " has been deleted.", "Deleted", MessageBoxButton.OK)
Dim aa = TryCast(DirectCast(Application.Current, App).RootFrame.Content, MainPage)
aa.SavedAccountslst.ItemsSource = Nothing
Dim directory As String = "./SafeLockPLUS/SavedAccounts/*.*"
Dim filenames As String() = Storage.GetFileNames(directory)
aa.SavedAccountslst.ItemsSource = filenames
NavigationService.GoBack()
End Sub
那是什么意思做的是,它会删除从viewaccount页面文件并清除SavedAccountList的项目,并重新加载它们都在ViewAccount页面,然后返回。
哪一行正是引发异常得空? –
aa.SavedAccountslst.ItemsSource = Nothing –
如果你在ViewAccount中,那么'App.RootFrame.Content'是'ViewAccount',而不是'MainPage',因此错误 –