Handling User Entry that's not in a Lookup Control
lazarus / 16-Databases

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SteveF · 2010-12-22 19:27

As someone migrating to Lazarus/FPC from MS Access, I'd like to know
if there is the equivalent of some Access behavior over here.

What I'm looking to do is replicate certain behavior of either a
Lookup Combo Box or Lookup List Box.  In Access both of these have a
Boolean property called LimitToList, and an event named OnNotInList.

When LimitToList is set to True, code can be added to the OnNotInList
event to gracefully handle what should be done when a user enters an
item that's not in the control's RowSource.  For example, a message
box could be shown:

"The item you entered is not in the list.
Do you want to add it?
  Yes       No"

If answered Yes, a modal dialog lets the user confirm that the entry
is correct, adds it to the table supplying the RowSource, and
refreshes the control so the user can select the new entry.

How can this be done in Lazarus?  I haven't been able to find similar
properties or events on Lazarus' Lookup data controls, but this
wouldn't be the first time I've missed something either obscure or
non-intuitive.  If these properties/events are not available,
suggestions/examples of how to do this in Lazarus would be welcome.

Steve

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SteveF · 2010-12-28 16:11

No takers?

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marcov · 2010-12-29 12:20

Afaik lookuplists in Delphi/Lazarus are basically a readonly entity,
so this would be hard.

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garlar27 · 2010-12-29 14:45

AFAIK you can't do that.

The items contained in a LookUp (Combo/ListBox) are taken from a
table. You can't add an item unless you add a record to the table
which the field/control is looking for.

What you CAN DO is add that value to a DBListBox or DBComboBox.

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SteveF · 2010-12-29 19:47

OK, that's what I kind of figured I'd have to do:  Use some other
controls to actually add the new item to the table/view, then refresh
the contents of the Lookup Combo.

Thanks for the confirmation.

Steve