I'm trying to have a custom function evaluated via a keyboard shortcut, and add this shortcut via the KeyEventTranslations.tr.

As a test example I took the example provided in this answer to add and evaluate the expression x=1 when pressing ctrl+u.

My only problem with that is that it leaves the x=1 expression on the notebook, while I don't want to see it. I therefore tried to delete it after evaluation, using the following:

Item[KeyEvent["u", Modifiers -> {Control}],
          FrontEnd`SelectionMove[FrontEnd`InputNotebook[], After, Cell];
            Cell[BoxData[RowBox[{"x", "=", "1"}]], "Input"]
          FrontEnd`SelectionMove[FrontEnd`InputNotebook[], Previous, Cell];
          FrontEnd`SelectionMove[FrontEnd`InputNotebook[], Previous, CellGroup, 1];

This is however not working for some reason. It seems to work up to the delete line (even though I didn't manage to properly select the whole cell group). When the last NotebookDelete line is added however, nothing seems to happen: the value of x is not changed at all and no expression is printer.

How can I modify this to have this toy expression (or any other expression) work in this way?

Of course, a way to just evaluate the expression without writing it in the notebook at all would be also appreciated!

  • 1
    $\begingroup$ Use KernelExecute. See for example what Rolf Mertig does here. If you need to work with a notebook but don't want it visible use FrontEnd`NotebookSuspendScreenUpdates like I do here $\endgroup$
    – b3m2a1
    Aug 27, 2017 at 19:14
  • $\begingroup$ that is actually what I first tried to do! I must have gotten some detail wrong because now I tried it again following the examples in that package and it works, thanks! If you want to add a brief answer I'll accept it, otherwise I'll selfanswer this one. $\endgroup$
    – glS
    Aug 27, 2017 at 19:21
  • $\begingroup$ @b3m2a1 by the way, do you know why my example didn't work? $\endgroup$
    – glS
    Aug 27, 2017 at 19:22
  • $\begingroup$ Have at it. I think your issue is that you need to encapsulate that in a list. My copy of Mathematica is currently frozen but FrontEndExecute takes a list for multiple commands as it's not Hold* so that should have all evaluated out to FrontEnd`NotebookDelete[FrontEnd`InputNotebook[]] before being passed to FrontEndExecute. $\endgroup$
    – b3m2a1
    Aug 27, 2017 at 19:25
  • $\begingroup$ @b3m2a1 I tried that but it still didn't work $\endgroup$
    – glS
    Aug 27, 2017 at 19:27

1 Answer 1


Following b3m2a1's advise, and the examples found in this package, the answer is to use KernelExecute instead of front end functions.

I added the following to the KeyEventTranslations.tr file in (modify path according to your OS) FileNameJoin@{$UserBaseDirectory, "SystemFiles", "FrontEnd", "TextResources", "Windows"}:

Item[KeyEvent["u", Modifiers -> {Control}],
        x = 1 + 1
    MenuEvaluator -> Automatic

and it works as intended (after restarting the front end).


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