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{include:Header, Design}
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Currently
...
events
...
are
...
handled
...
very
...
bad
...
since
...
everything
...
is
...
subscribed
...
to
...
everything
...
(Project
...
explorer
...
to
...
Model.DataItems.Added/Removed,
...
Folder.DataItems.Added/Removed,
...
etc.).
...
As
...
result
...
it
...
makes
...
things
...
very
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difficult
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to
...
manage
...
when
...
objects
...
are
...
added
...
/
...
removed.
...
Especially
...
when
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these
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subsciption
...
happen
...
in
...
external
...
plugins
...
(HABITAT,
...
Verkenner...).
...
Better
...
way
...
to
...
inform
...
containers
...
of
...
the
...
collections
...
is
...
to
...
inform
...
parent
...
about
...
changes
...
(INotifyPropertyChanged)
...
of
...
the
...
underlying
...
object
...
or
...
let
...
only
...
container
...
subscribe
...
to
...
collection
...
contained
...
in
...
it.
...
In
...
a
...
few
...
words:
...
Arrows
...
show
...
what
...
object
...
is
...
subscribed
...
to
...
what.
...
Allowed
...
Subscription
...
of events
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events
{flowchart}"SomeHighLevelType" -> "IEventedList<SomeType>" -> "SomeType"{flowchart} |
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{flowchart} "Gui Form containing instance of SomeType" -> "SomeType" {flowchart} |
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{flowchart}
"Gui Form containing instance of SomeHighLevelType" -> "SomeHighLevelType"
{flowchart}
h3. * |
Anti-Pattern
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* {flowchart} "Gui Form containing instance of SomeHighLevelType" -> "SomeHighLevelType" -> "IEventedList<SomeType>" -> "SomeType" "Gui Form containing instance of SomeHighLevelType" -> "IEventedList<SomeType>" [ label = "DON'T" ]; "Gui Form containing instance of SomeHighLevelType" -> "SomeType" [ label = "DON'T" ]; {flowchart} |
In
...
general
...
the
...
rule
...
is:
...
when
...
you
...
need
...
to
...
Subscribe
...
/
...
Unsubscribe
...
frequently
...
to
...
events
...
-
...
you
...
have
...
to
...
review
...
your
...
design
...
of
...
how
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event
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subscription
...
is
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organized.
...
Consequences
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for
...
DelftShell
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- Refactor
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- all
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- subscription
...
- of
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- events
...
- in
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- ProjectExplorer,
...
- HABITAT,
...
- etc.
...
Points
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of
...
interest
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- INotifyPropertyChanging
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- in
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- .NET
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- 3.5
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- WeakEvent
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- in
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- .NET
...
- 3.5
...