如何覆盖TextBlock.GetTextPositionFromPoint？

是否有可能重写方法如何覆盖TextBlock.GetTextPositionFromPoint？

public TextPointer GetPositionFromPoint(Point point, bool snapToText);

一个WPF的TextBlock的

？

我的类从TextBlock的继承，但我得到一个例外，如果我设置

TextTrimming="CharacterEllipsis"

和移动鼠标点（“...”）。

Exception: 

Message: The requested distance is outside the content of the associated document. 
Stacktrace: 
bei System.Windows.Documents.TextPointer.InitializeOffset(TextPointer position, Int32 distance, LogicalDirection direction) 
bei System.Windows.Documents.TextPointer.System.Windows.Documents.ITextPointer.CreatePointer(Int32 offset, LogicalDirection gravity) 
bei System.Windows.Controls.TextBlock.GetTextPositionFromDistance(Int32 dcp, Double distance, Double lineVOffset, Int32 index) 
bei MS.Internal.Text.TextLineResult.GetTextPositionFromDistance(Double distance) 
bei MS.Internal.Documents.TextParagraphView.GetTextPositionFromPoint(ReadOnlyCollection`1 lines, Point point, Boolean snapToText) 
bei MS.Internal.Documents.TextParagraphView.GetTextPositionFromPoint(Point point, Boolean snapToText) 
bei MS.Internal.Documents.TextViewBase.System.Windows.Documents.ITextView.GetTextPositionFromPoint(Point point, Boolean snapToText) 
bei System.Windows.Documents.TextEditorMouse.IsPointWithinInteractiveArea(TextEditor textEditor, Point point) 
bei System.Windows.Documents.TextEditorMouse.OnQueryCursor(Object sender, QueryCursorEventArgs e) 
bei System.Windows.RoutedEventArgs.InvokeHandler(Delegate handler, Object target) 
bei System.Windows.RoutedEventHandlerInfo.InvokeHandler(Object target, RoutedEventArgs routedEventArgs) 
bei System.Windows.EventRoute.InvokeHandlersImpl(Object source, RoutedEventArgs args, Boolean reRaised) 
bei System.Windows.UIElement.RaiseEventImpl(DependencyObject sender, RoutedEventArgs args) 
bei System.Windows.UIElement.RaiseTrustedEvent(RoutedEventArgs args) 
bei System.Windows.Input.InputManager.ProcessStagingArea() 
bei System.Windows.Input.InputManager.ProcessInput(InputEventArgs input) 
bei System.Windows.Input.MouseDevice.UpdateCursorPrivate() 
bei System.Windows.Input.MouseDevice.PostProcessInput(Object sender, ProcessInputEventArgs e) 
bei System.Windows.Input.InputManager.RaiseProcessInputEventHandlers(ProcessInputEventHandler postProcessInput, ProcessInputEventArgs processInputEventArgs) 
bei System.Windows.Input.InputManager.ProcessStagingArea() 
bei System.Windows.Input.InputManager.ProcessInput(InputEventArgs input) 
bei System.Windows.Input.InputProviderSite.ReportInput(InputReport inputReport) 
bei System.Windows.Interop.HwndMouseInputProvider.ReportInput(IntPtr hwnd, InputMode mode, Int32 timestamp, RawMouseActions actions, Int32 x, Int32 y, Int32 wheel) 
bei System.Windows.Interop.HwndMouseInputProvider.FilterMessage(IntPtr hwnd, WindowMessage msg, IntPtr wParam, IntPtr lParam, Boolean& handled) 
bei System.Windows.Interop.HwndSource.InputFilterMessage(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled) 
bei MS.Win32.HwndWrapper.WndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled) 
bei MS.Win32.HwndSubclass.DispatcherCallbackOperation(Object o) 
bei System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Int32 numArgs) 
bei System.Windows.Threading.ExceptionWrapper.TryCatchWhen(Object source, Delegate callback, Object args, Int32 numArgs, Delegate catchHandler)

捕捉异常我想overide base.GetPositionFromPoint（Point point，bool snapToText）。

但以下从来没有被击中：

public new TextPointer GetPositionFromPoint(Point point, bool snapToText) { 
    try { 
    return base.GetPositionFromPoint(point, snapToText); 
    } 
    catch (Exception) { 
    return null; 
    } 
}

有什么不对？

来源

2017-10-16 cew3

该方法未标记为“虚拟”，因此您无法覆盖它 – Evk

是否有可能重写WPF TextBlock的方法GetPositionFromPoint？

不可以。您不能覆盖未标记为virtual的方法。

你的确可以隐藏使用new关键字的方法，但是这不会让你的虚拟和重载方法的多态behvaiour，即WPF不会打电话给你的方法，这就是为什么你的断点永远不会被打。

Is it possible to override a non-virtual method?

来源

2017-10-16 12:01:30 mm8

如何覆盖TextBlock.GetTextPositionFromPoint？

回答

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