CoreTextServicesManager не работает должным образом

Я не уверен, что вы уже видели это (поздний ответ после того, как я нашел этот вопрос в Google), но, к сожалению, поддержка некоторых API-интерфейсов UWP была прекращена. В этой статье предлагаются некоторые замены и обходные пути для некоторых из них. https://learn.microsoft.com/en-gb/windows/apps/desktop/modernize/desktop-to-uwp-supported-api

У нас это работает в нашем приложении UWP. Убедитесь, что вы находитесь в основной теме

        imeInputPane = CoreInputView.GetForCurrentView();
        imeInputPane.PrimaryViewShowing += ImeInputPane_PrimaryViewShowing;
        imeInputPane.PrimaryViewHiding += ImeInputPane_PrimaryViewHiding;

        imeTextContext = CoreTextServicesManager.GetForCurrentView().CreateEditContext();

        // Manually control when soft keyboard shows.  When hard keyboard is attached, the
        // soft keyboard will never show.
        imeTextContext.InputPaneDisplayPolicy = CoreTextInputPaneDisplayPolicy.Manual;

        // the default keyboard is general purpose soft keyboard, has no affect with hard keyboard
        imeTextContext.InputScope = CoreTextInputScope.Text;

        imeTextContext.TextRequested += IMETextContext_TextRequested;
        imeTextContext.SelectionRequested += IMETextContext_SelectionRequested;
        imeTextContext.FocusRemoved += IMETextContext_FocusRemoved;
        imeTextContext.TextUpdating += IMETextContext_TextUpdating;
        imeTextContext.SelectionUpdating += IMETextContext_SelectionUpdating;
        imeTextContext.FormatUpdating += IMETextContext_FormatUpdating;
        imeTextContext.LayoutRequested += IMETextContext_LayoutRequested;
        imeTextContext.CompositionStarted += IMETextContext_CompositionStarted;
        imeTextContext.CompositionCompleted += IMETextContext_CompositionCompleted;

...

    private void IMETextContext_TextUpdating(CoreTextEditContext sender, CoreTextTextUpdatingEventArgs args)
    {
         string origText = imeText;
         CoreTextRange range = args.Range;
         CoreTextRange newSelection = args.NewSelection;
        
         //Modify the internal text store for the IME
         imeText = imeText.Substring(0, range.StartCaretPosition)
              + args.Text
              + imeText.Substring(Math.Min(imeText.Length, 
              range.EndCaretPosition));
        
         newSelection.EndCaretPosition = newSelection.StartCaretPosition;
        
         Debug.WriteLine(string.Format("IME SendReplaceText Orig Text '{0}'  New Text '{1}'  StartCaret '{2}'  EndCaret '{3}'", origText, imeText, imeSelection.StartCaretPosition, imeSelection.EndCaretPosition - imeSelection.StartCaretPosition));
        
         // Do something with the text
         SendReplaceText(args.Text                               // new text
              , range.StartCaretPosition                           // start position
              , range.EndCaretPosition - range.StartCaretPosition  // length of former text that is being replaced
              , args.Text.Length);                                 // length of the modified text
        
         imeSelection = newSelection;
         args.Result = CoreTextTextUpdatingResult.Succeeded;
    }
        
    private void IMEBypassControl_OnShowKeyboard(object sender, IMEBypassShowKeyboardEventArgs e)
    {
         try
         {
              if (e.Visible)
              {
                  Task.Run(async () =>
                  {
                      if (MiscUtils.AreWeOnMainUIThread)
                      {
                          try
                          {
                              LOG.LogV(string.Format("IME Show Keyboard '{0}' Start '{1}'  Total Size '{2}", e.Text, e.CursorPosition, e.FetchSize));
        
                              //Debug.WriteLine(string.Format("IME Show Keyboard '{0}' Start '{1}'  Total Size '{2}", e.Text, e.CursorPosition, e.FetchSize));
                              imeTextContext.InputScope = CoreTextInputScope.Text;
                              imeText = e.Text;
                              imeSelection.StartCaretPosition = e.CursorPosition;
                              imeSelection.EndCaretPosition = e.CursorPosition;
                                            
                              imeTextContext.NotifyTextChanged(imeSelection, e.Text.Length, imeSelection);
        
                              SetFocus();
                          }
                          catch (Exception ex)
                          {
                              LOG.LogE(ex);
                          }
                      }
                      else
                      {
                          await MiscUtils.CallOnMainViewUiThreadAsync(() =>
                          {
                          try
                          {
                              LOG.LogV(string.Format("IME Show Keyboard '{0}' Start '{1}'  Total Size '{2}", e.Text, e.CursorPosition, e.FetchSize));
        
                              //Debug.WriteLine(string.Format("IME Show Keyboard '{0}' Start '{1}'  Total Size '{2}", e.Text, e.CursorPosition, e.FetchSize));
                              imeTextContext.InputScope = CoreTextInputScope.Text;
                              imeText = e.Text;
                              imeSelection.StartCaretPosition = e.CursorPosition;
                              imeSelection.EndCaretPosition = e.CursorPosition;
                                            
                              imeTextContext.NotifyTextChanged(imeSelection, e.Text.Length, imeSelection);
        
                              SetFocus();
                          }
                          catch (Exception ex)
                          {
                              LOG.LogE(ex);
                          }
                          });
                      }
                  }).GetAwaiter().GetResult();
              }
              else
              {
                  RemoveFocus();
              }
          }
          catch (Exception ex)
          {
              LOG.LogE(ex);
          }
      }
      else
      {
          RemoveFocus();
      }
  }

  private void SetFocus()
  {
      imeTextContext.NotifyFocusEnter();
  }

  public void RemoveFocus()
  {
      if (MiscUtils.AreWeOnMainUIThread)
      {
          imeTextContext.NotifyFocusLeave();
          imeInputPane.TryHide();
      }
      else
      {
          Task.Run(async () =>
          {
               await MiscUtils.CallOnMainViewUiThreadAsync(() =>
               {
                   imeTextContext.NotifyFocusLeave();
                   imeInputPane.TryHide();
               });
          }).GetAwaiter().GetResult();
      }
  }