Background printing

rbuser

i've enabled background printing capabilities
but it doesn't seem to work when i first present a print preview
when in the print preview i ask to print it simply doesn't do a thing, no
error, nothing
when i uncheck the background printing option all goes well
the report is getting its data from local memory datasets that aren't used
by other processes so that can't be the problem i guess
any ideas on where to start looking?
tia,
marc

nicocizik

Hi Marc,

Please see the following examples on how to use the background printing
feature in ReportBuilder.

http://www.digital-metaphors.com/tips/BackgroundPrintDemos.zip

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rbuser

Nico,
before digging into the examples i've read the help file
correct me if i'm wrong:
when RB is going into another thread it makes a new instance of the
datamodule to launch itself and do the printing?
in that case it will not work cause i firstly have to move the data into the
memdatasets in the datamodule and those are empty when the dataset is
created of course
is there a way to print my memdatasets in background using RB (is this
documented in the samples?)

tia,
marc

nicocizik

Hi Marc,

When are the memory datasets filled, or even opened? I assume when you open
these datasets they are either filled or some event code is executed to fill
them automatically. You could possibly use the TppDataPipeline.Open event
to open your memory datsets so they contain data before the report is
printed. I'm just a bit unclear about how your data access is set up
because it seems like it should work.

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rbuser

Nico,

well thats the problem, i now first fill the memdatasets before i start the
printing job
so what you are saying is that i should fill the datasets in the onopen
event but at that point i have to get to objects who reside in the main
thread and i don't even know if they still exists at that point
so as i see it now the only thing i can do to make it work is to somehow
write the memdata to a file and load it in the memdatasets when the onopen
event is fired
but then i have to deal with concurrency problems (potentially there are
more than one instance running of the same app and printing at the same
time, abstraction of the fact that i somehow have to pass the filename var
but i guess thats a minor problem
any other insights?
tia,
marc

nardmoseley

You could also try opening the memdatasets in the OnCreate event of the
Form/DataModule.

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Nard Moseley
Digital Metaphors Corporation
www.digital-metaphors.com

rbuser

Nard hi!
no not possible,
i'm passing a complex object-list-hiarchy
to the created datamodule
what i could try to do though is to create those memdata in another
datamodule and somehow pass that reference into the creation of the
datamodule...not sure how to do that but i think that is the only possiblity
left...
thx!
marc