Hello,
I have a more ore or less complicated business object, that looks
similar to this:
<Entry>
has some properties (id, pubdate...)
and a list of <Version>s
each <Version> has a language, a title and a description and a list of
<Image>s
each <Image>, has a List of <ImageInfo>s with Title and Description
To edit the objects properties I created a similar structure of controls
<EntryControl> has some Textboxes and a Tabstrip, holdig Tabs
corresponding to <Version>s, again holding some Textboxes a list of
<ImagesControl>s with their <ImageInfoControl>s.
The question is, should the control A) know of the business object it
represents?
Should I instantiate EntryControl like this?
Entry e = EntryFactory.GetEntry("abc");
EntryControl ec = new EntryControl(e);
and "inside" of EntryControl my Properties would be
public string Id {
get { return entry.Id; }
set {
entry Id = value;
TextBoxId.Text = value;
}
}
and have problems, once the user edits the fields, a call to Id, would
still yield the object's value and not the textbox' new text value.
But I'd have the advantage (still in Entry) that I could much better
encapsulate the child controls creation and logic.
public EntryControl(Entry entry) {
versionControl.Versions = entry.Versions // now I can encapsulate
// everything onwards in
// VersionControl
}
or B) should my Controls be completely agnostic containers of agnostic
sub controls
Instead:
class EntryControl {
private Textbox textBoxId, textBoxPubDate;
public string Id {
get {return textBoxId.Text; }
set {textBoxId.Text = value; }
}
public VersionControl VersionControl;
}
class Client {
void DoSomething() {
Entry e = Entry.GetEntry("abc");
EntryControl ec = new EntryControl;
ec.Id = e.Id;
ec.VersionControl = new VersionControl();
foreach(Version v in e.Versions) {
VersionTab tab = new VersionTab(); // this will be difficult to
// read back later. What
if the
// user inserts a new version
// in the middle...?
tab.Title = v.Title;
}
}
}
What is your opinion? What is the best pattern in relation business
objects vs controls.
To me it seems version A encapsulates better, is easier to read and is
more comfortable to use. But concurrency makes it less attractive;
B has the advantage of dumb controls that cannot do anything wrong,
but writing the client code is an ugly hack.
Any beautiful patterns?
--
Jan
www.limpens.com
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