Unregistering a child from a Dataflow about dataflowex

[karldodd]

@cameronwhite08 At this moment we don't support un-register a dataflow block. But adding UnregisterChild() shouldn't be too difficult. Could you shed some light on any scenario where this feature is useful?

[slvrfn]

UnregisterChild() could be particularly useful in complex dataflows. In my own experience, if there is a dataflow block that could be expected to fault, it could be more useful to unregister then recreate that particular block and re-register it than recreate the entire data flow again. When re-creating an entire dataflow, some of the internal data being processed could be lost.

[karldodd]

Thanks for the reply. I try to understand your example. Well, instead of 'unregister and recreate', why not prevent the block from being faulted at all (like putting a try-catch in an actionblock/transformblock)? And under which real-world scenario is a block 'expected to fault'?

[slvrfn]

You bring up a good point, in fact this is what I have done in my own work since the UnregisterChild is not present (yet). Another point though is if a fault unexpectedly happens. A user could set up the ability of a flow to track state of each individual block and when an unexpected fault occurs could 'unregister and recreate' the faulted block, probably skipping the data item that caused the fault.