Re: DynamicModule values not saved correctly in "docked" cells?

*To*: mathgroup at smc.vnet.net*Subject*: [mg131577] Re: DynamicModule values not saved correctly in "docked" cells?*From*: Chris Osborn <chrisosb at gmail.com>*Date*: Sat, 7 Sep 2013 06:03:52 -0400 (EDT)*Delivered-to*: l-mathgroup@mail-archive0.wolfram.com*Delivered-to*: l-mathgroup@wolfram.com*Delivered-to*: mathgroup-outx@smc.vnet.net*Delivered-to*: mathgroup-newsendx@smc.vnet.net*References*: <20130902064730.41C8E6A02@smc.vnet.net> <l09s4f$ja7$1@smc.vnet.net>

Hi John, Thanks very much for your very thorough answer; it is quite helpful. Chris On Thursday, September 5, 2013 5:06:39 AM UTC-7, John Fultz wrote: > Yes, it is expected. Docked cells are built from the expression on the > > rhs of the DockedCells option, and this option only changes when you > > explicitly set the option. So, the in-memory docked cell may have > > updated values, but these values will not be written to disk or MathLink > > because doing so would require rewriting the rhs of the DockedCells > > option (which might be impossible to do with full fidelity). > > > > One easy way to deal with this issue is to use TaggingRules at the > > notebook level as a sort of notebook-level DynamicModule variable. > > Here's an example function to replace your content[] function for docked > > cells: > > > > dockedCellContent[] := > > Button[Dynamic[ > > CurrentValue[EvaluationNotebook[], {TaggingRules, "x"}, > > RandomReal[]]], > > CurrentValue[EvaluationNotebook[], {TaggingRules, "x"}]++] > > > > The technique is documented in the help system. Look up the topic > > tutorial/StoringAndTrackingPaletteStates. However, I'm adding one novel > > thing here which isn't documented there, which is the third argument of > > CurrentValue. I could have initialized the CurrentValue[] by doing > > something like: > > > > DynamicModule[{}, (* body *), = > > Initialization:>If[CurrentValue[EvaluationNotebook[], {TaggingRules, > > "x"}]===Inherited,CurrentValue[EvaluationNotebook[], > > {TaggingRules, "x"}]=RandomReal[]]] > > > > but this undocumented third argument does exactly that much more > > conveniently, and the format is unlikely to change (and probably will > > get documented in a future version). > > > > John Fultz > > jfultz at wolfram.com > > User Interface Group > > Wolfram Research, Inc. > > > > > > > > On Sep 2, 2013, at 1:47 AM, Chris Osborn <chrisosb at gmail.com> wrote: > > > > > It appears that for a DynamicModule expression in a "docked" cell, > > symbol assignments are not correctly saved when saving the associated > > notebook. > > > > > > In particular, when I save, close, and then reopen such a notebook, I > > find that the value assigned to each DynamicModule symbol is the initial > > value assigned to it, and not the value it had when the notebook was > > saved. > > > > > > Is this behavior expected? > > > > > > > > > I have written some code, included below, to demonstrate this issue > > (tested on Mathematica 9.0.1.0). The code creates a new notebook with > > one docked cell and one non-docked cell. Both cells have DynamicModule > > expressions with a single variable in them, and have buttons that > > increment the value of their respective variables. To reproduce my > > issue: > > > > > > 1. Execute the code I give below > > > 2. In that notebook that is created, click the button in each cell a > > few times, causing the values displayed in the buttons to increase by 1 > > each time > > > 3. Save the notebook and close it > > > 4. Re-open the notebook > > > > > > The value in the non-docked cell will be as expected; the value in the > > docked cell will be the original value (before clicking the button.) > > Here is the code: > > > > > > ClearAll[content]; > > > content[] := > > > DynamicModule[{x}, > > > x = Random[]; > > > Button[Dynamic[x], x++] > > > ]; > > > > > > CreateDocument[ > > > {content[]}, > > > DockedCells -> Cell[BoxData@ToBoxes@content[], "DockedCell"] > > > ]; > > > > > > > > > > > > Much thanks in advance for any suggestions! > > > > > > > > > Thanks, > > > Chris > > >

**References**:**DynamicModule values not saved correctly in "docked" cells?***From:*Chris Osborn <chrisosb@gmail.com>