Question

我使用Xceed.Wpf.Toolkit.MessageBox来显示一个对话框，我需要动态设置样式。

当我可以访问UI调度程序时，我只需调用Show()方法，并将样式作为参数传递就可以了。

但是当我无权访问UI线程时，我会写

Application.Current.Dispatcher.Invoke(DispatcherPriority.Normal, new Action(() =>
{
    MessageBox.Show("Message Text", ..., myStyle);
}));

这样做，我得到一个例外：

由于另一个线程拥有该对象，因此调用线程无法访问该对象。

当然，从参数中删除样式时，不会引发任何异常。
myStyle是直接在方法中创建的，没有从其他线程或其他东西传递过来。

有人知道为什么会发生这种情况以及如何解决该问题吗？

堆栈跟踪：

at System.Windows.Threading.Dispatcher.VerifyAccess()
at System.Windows.Style.CheckTargetType(Object element)
at System.Windows.StyleHelper.UpdateStyleCache(FrameworkElement fe, FrameworkContentElement fce, Style oldStyle, Style newStyle, Style& styleCache)
at System.Windows.FrameworkElement.OnStyleChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
at System.Windows.DependencyObject.OnPropertyChanged(DependencyPropertyChangedEventArgs e)
at System.Windows.FrameworkElement.OnPropertyChanged(DependencyPropertyChangedEventArgs e)
at System.Windows.DependencyObject.NotifyPropertyChange(DependencyPropertyChangedEventArgs args)
at System.Windows.DependencyObject.UpdateEffectiveValue(EntryIndex entryIndex, DependencyProperty dp, PropertyMetadata metadata, EffectiveValueEntry oldEntry, EffectiveValueEntry& newEntry, Boolean coerceWithDeferredReference, Boolean coerceWithCurrentValue, OperationType operationType)
at System.Windows.DependencyObject.SetValueCommon(DependencyProperty dp, Object value, PropertyMetadata metadata, Boolean coerceWithDeferredReference, Boolean coerceWithCurrentValue, OperationType operationType, Boolean isInternal)
at System.Windows.DependencyObject.SetValue(DependencyProperty dp, Object value)
at Xceed.Wpf.Toolkit.MessageBox.ShowCore(Window owner, IntPtr ownerHandle, String messageText, String caption, MessageBoxButton button, MessageBoxImage icon, MessageBoxResult defaultResult, Style messageBoxStyle)
at Xceed.Wpf.Toolkit.MessageBox.Show(Window owner, String messageText, String caption, MessageBoxButton button, MessageBoxImage icon, MessageBoxResult defaultResult, Style messageBoxStyle)
at MyNamespace.MyClass.<>c__DisplayClass1_0.<MyMethod>b__4() in C:\MyFile.cs:line 94
at System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Int32 numArgs)
at System.Windows.Threading.ExceptionWrapper.TryCatchWhen(Object source, Delegate callback, Object args, Int32 numArgs, Delegate catchHandler)
at System.Windows.Threading.DispatcherOperation.InvokeImpl()
at MS.Internal.CulturePreservingExecutionContext.CallbackWrapper(Object obj)
at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
at MS.Internal.CulturePreservingExecutionContext.Run(CulturePreservingExecutionContext executionContext, ContextCallback callback, Object state)
at System.Windows.Threading.DispatcherOperation.Invoke()
at System.Windows.Threading.Dispatcher.ProcessQueue()
at System.Windows.Threading.Dispatcher.WndProcHook(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 System.Windows.Threading.ExceptionWrapper.TryCatchWhen(Object source, Delegate callback, Object args, Int32 numArgs, Delegate catchHandler)
at System.Windows.Threading.Dispatcher.LegacyInvokeImpl(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.Window.ShowHelper(Object booleanBox)
at System.Windows.Window.ShowDialog()

Answer 1

您无法在后台线程上创建myStyle，然后将其应用于调度程序线程上的控件。您需要在同一调度程序线程上创建它：

Application.Current.Dispatcher.Invoke(DispatcherPriority.Normal, new Action(() =>
{
    //create myStyle here...
    var myStyle = ...;
    MessageBox.Show("Message Text", ..., myStyle);
}));

WPF工具箱MessageBox样式异常

1 个答案: