Fix: Fixed NullReferenceException in InvertSelectionAction

[hishitetsu]

Resolved / Related Issues

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Files.App.Actions InvertSelectionAction.get_IsExecutable () ABI.System.Windows.Input.ICommand Vftbl.Do_Abi_CanExecute_2 (IntPtr thisPtr, IntPtr parameter, Byte* result) WinRT ExceptionHelpers.<ThrowExceptionForHR>g__Throw|39_0 (Int32 hr) ABI.System.EventHandler NativeDelegateWrapper.Invoke (Object sender, EventArgs args) CommunityToolkit.Mvvm.ComponentModel ObservableObject.SetProperty[T] (T& field, T newValue, String propertyName) Files.App.Data.Contexts ContentPageContext.UpdatePageType () CommunityToolkit.Mvvm.ComponentModel ObservableObject.SetProperty[T] (T& field, T newValue, String propertyName) Files.App.Data.Models CurrentInstanceViewModel.set_IsPageTypeNotHome (Boolean value) Files.App.Views.Layouts BaseLayoutPage.OnNavigatedTo (NavigationEventArgs e) System.Threading.Tasks.Task <>c.<ThrowAsync>b__128_0 (Object state) Microsoft.UI.Dispatching.DispatcherQueueSynchronizationContext <>c__DisplayClass2_0.<Post>b__0 () WinRT ExceptionHelpers.<ThrowExceptionForHR>g__Throw|39_0 (Int32 hr) ABI.Windows.ApplicationModel.Core IUnhandledErrorMethods.Propagate (IObjectReference _obj) Microsoft.AppCenter.Utils ApplicationLifecycleHelperWinUI.<ctor>b__0_3 (Object sender, UnhandledErrorDetectedEventArgs eventArgs) 

Validation
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• Did you remove any strings from the en-us resource file?
  • Did you search the solution to see if the string is still being used?
• Did you implement any design changes to an existing feature?
  • Was this change approved?
• Are there any other steps that were used to validate these changes?

[yaira2]

LGTM