线程问题?

cmssoen2  于 2021-07-09  发布在  Java
关注(0)|答案(1)|浏览(322)

我一直在尝试将现有的c#wpfapi与java应用程序接口。
到目前为止,我已经成功地使用jni4net来生成java和.net代码之间接口的代理。
此集成在显示wpf ui时产生了sta线程问题:

System.InvalidOperationException: The calling thread must be STA, because many UI components require this.
  at System.Windows.Input.InputManager..ctor()
  at System.Windows.Input.InputManager.GetCurrentInputManagerImpl()
  at System.Windows.Input.KeyboardNavigation..ctor()
  at System.Windows.FrameworkElement.FrameworkServices..ctor()
  at System.Windows.FrameworkElement.EnsureFrameworkServices()
  at System.Windows.FrameworkElement..ctor()
  at System.Windows.Controls.Control..ctor()
  at System.Windows.Window..ctor()

通过使用以下模式加载wpf ui的using showdialog,可以克服这一问题:

Thread thread = new Thread(new ParameterizedThreadStart(ParameterizedMethodName));
thread.SetApartmentState(ApartmentState.STA);
thread.Start(parameter);
thread.Join();

但是,现在我遇到了类似于以下的异常,在使用wpf ui时,单击鼠标或按键可以触发以下事件(此示例来自鼠标单击):

System.InvalidOperationException: The calling thread cannot access this object because a different thread owns it.
  at System.Windows.Threading.Dispatcher.VerifyAccess()
  at System.Windows.DependencyObject.GetValue(DependencyProperty dp)
  at System.Windows.Input.InputBinding.get_Command()
  at System.Windows.Input.InputBindingCollection.FindMatch(Object targetElement, InputEventArgs inputEventArgs)
  at System.Windows.Input.CommandManager.TranslateInput(IInputElement targetElement, InputEventArgs inputEventArgs)
  at System.Windows.UIElement.OnMouseDownThunk(Object sender, MouseButtonEventArgs e)
  at System.Windows.Input.MouseButtonEventArgs.InvokeEventHandler(Delegate genericHandler, Object genericTarget)
  at System.Windows.RoutedEventArgs.InvokeHandler(Delegate handler, Object target)
  at System.Windows.RoutedEventHandlerInfo.InvokeHandler(Object target, RoutedEventArgs routedEventArgs)
  at System.Windows.EventRoute.InvokeHandlersImpl(Object source, RoutedEventArgs args, Boolean reRaised)
  at System.Windows.UIElement.RaiseEventImpl(DependencyObject sender, RoutedEventArgs args)
  at System.Windows.UIElement.RaiseTrustedEvent(RoutedEventArgs args)
  at System.Windows.UIElement.RaiseEvent(RoutedEventArgs args, Boolean trusted)
  at System.Windows.Input.InputManager.ProcessStagingArea()
  at System.Windows.Input.InputManager.ProcessInput(InputEventArgs input)
  at System.Windows.Input.InputProviderSite.ReportInput(InputReport inputReport)
  at System.Windows.Interop.HwndMouseInputProvider.ReportInput(IntPtr hwnd, InputMode mode, Int32 timestamp, RawMouseActions actions, Int32 x, Int32 y, Int32 wheel)
  at System.Windows.Interop.HwndMouseInputProvider.FilterMessage(IntPtr hwnd, WindowMessage msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
  at System.Windows.Interop.HwndSource.InputFilterMessage(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
  at MS.Win32.HwndWrapper.WndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
  at MS.Win32.HwndSubclass.DispatcherCallbackOperation(Object o)
  at System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Int32 numArgs)
  at MS.Internal.Threading.ExceptionFilterHelper.TryCatchWhen(Object source, Delegate method, Object args, Int32 numArgs, Delegate catchHandler)
  at System.Windows.Threading.Dispatcher.InvokeImpl(DispatcherPriority priority, TimeSpan timeout, Delegate method, Object args, Int32 numArgs)
  at MS.Win32.HwndSubclass.SubclassWndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam)
  at MS.Win32.UnsafeNativeMethods.DispatchMessage(MSG& msg)
  at System.Windows.Threading.Dispatcher.PushFrameImpl(DispatcherFrame frame)
  at System.Windows.Threading.Dispatcher.PushFrame(DispatcherFrame frame)
  at System.Windows.Window.ShowHelper(Object booleanBox)
  at System.Windows.Window.Show()
  at System.Windows.Window.ShowDialog()

我目前不确定如何解决这个问题,并从堆栈跟踪中确定问题的原因。
非常感谢您的帮助/建议。

ngynwnxp

ngynwnxp1#

关于解决办法我不能提供太多建议,但我可以告诉你问题所在。所有wpf代码都必须在同一个线程上运行(可能是您正在创建的线程)。您遇到的错误是,有人试图从其他线程访问wpf控件。
假设您有一个显示对话框的api调用和java代码调用 MyApi.ShowDialog . 你的api ShowDialog 方法不能简单地调用 MyDialog.ShowDialog() 因为对ui组件的调用将来自java线程。相反,您的api需要足够聪明,以便将这些调用封送到适当的wpf(ui)线程。
所以它应该这样做:

if(!CheckAccess())
    MyDialog.Dispatcher.BeginInvoke(DeleageToShowDialog);

不幸的是,这可能意味着您必须在api上做大量工作,因为它可能无法解决这样的线程问题。

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