So here is some code that successfully displays a slider, the value of a dynamic variable, and cycles through a list of 10 images titled 'imgs' with keyboard commands.

 Column@{Slider[Dynamic[y], {1, 10, 1}], Dynamic@y, 
   CellEventActions -> {"LeftArrowKeyDown" :> (y = 
    Evaluate[Max[1, y - 1]]), 
    "RightArrowKeyDown" :> (y = Evaluate[Min[10, y = y + 1]])}]

However, when I put this code into DynamicModule[{y},"Insert previous block of code here"]

The keyboard functionality ceases and when trying to use the keyboard I get there error: "Recursion depth of 1024 exceeded during evaluation of -1+y$$."

How can I get the CellEventActions to work properly within DynamicModule?

Much thanks in advance!


1 Answer 1


This should work as you expect:

  TextCell[Column@{Slider[Dynamic[y], {1, 10, 1}], Dynamic@y, Dynamic[imgs[[y]]]}, 
   CellEventActions -> {"LeftArrowKeyDown" :> (y = Max[1, y - 1]; 
       SelectionMove[InputNotebook[], After, ButtonCell]), 
     "RightArrowKeyDown" :> (y = Min[10, y = y + 1]; 
       SelectionMove[InputNotebook[], Before, ButtonCell]), 
     PassEventsDown -> True}, ShowSelection -> False]]]

The first change I have done is to use CellPrint instead of ExpressionCell and thus avoiding the recursion depth error. Then I used SelectionMove so to keep the selection inside the cell, after the operation on y is done. I hope this is what you are looking for.

  • $\begingroup$ Thank you! Works great. SelectionMove is something new for me, thanks for sharing. $\endgroup$
    – DarrenM
    Jun 22, 2015 at 17:56

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