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Consider the following code:

timesXpressed = 0;
SetOptions[EvaluationNotebook[], 
 NotebookEventActions -> {{"KeyDown", "x"} :> timesXpressed++}]
Dynamic[timesXpressed]

It counts the number of times the key x is pressed. However, in intercepting the key presses, they're no longer actually typed in the notebook. I suspect adding an additional action to type x in the notebook when the key is down might fix this, but I don't know such an action.

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  • $\begingroup$ I cannot replicate this behavior on v12.2.0 Win7-x64. Only when "x" is pressed in the notebook does it change the timesXpressed. Please run $Version and include this information. $\endgroup$
    – Syed
    Commented Nov 21, 2021 at 12:54
  • $\begingroup$ ref/NotebookEventActions/Details: The default behavior can be changed by including rules for PassEventsDown or PassEventsUp in the list given as the setting for NotebookEventActions. $\endgroup$
    – rnotlnglgq
    Commented Nov 21, 2021 at 13:10

1 Answer 1

Reset to default
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timesXpressed = 0;
SetOptions[EvaluationNotebook[], 
 NotebookEventActions -> {{"KeyDown", "x"} :> (timesXpressed++; 
     FrontEndExecute[NotebookWrite[InputNotebook[], "x"]])}]
Dynamic[timesXpressed]
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  • $\begingroup$ This is exactly what I was looking for. Thanks. $\endgroup$
    – user3257842
    Commented Nov 21, 2021 at 14:18
  • $\begingroup$ Is there any way to do logical combinations on these events, for example an action when {"KeyDown", "x"} or {"KeyDown", "X"} ? $\endgroup$
    – user3257842
    Commented Nov 21, 2021 at 17:38
  • 1
    $\begingroup$ Just add another Keydown action, e.g. NotebookEventActions -> {{"KeyDown", "x"} :> (timesX... , "x"]), {"KeyDown", "X"} :> (timesX... , "X"])} $\endgroup$
    – Chris Degnen
    Commented Nov 21, 2021 at 21:23

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