How to use DBLookupCombobox?
lazarus / 16-Databases

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Hansvb · 2023-01-15 09:50

Hi,

I am using query1 to retrieve data from a table. Then I retrieve a
code list with query2. I display this code list in a dbgrid using a
dblookupcombobox. It works fine the first time. (small error, i see
the ID value and not the Name value).
When I run query1 again to retrieve data from another table, I get the
warning that a query1 field x is not found. The query is good because
if it runs the first time then I don't get an error. If I don't assign
a dblookupcombobox to the dbgrid then I can repeat query1 as many
times on different tables with different fields as I want. It works.
Somehow the dblookupcombox seems to hold some realtion with
query1which I can't find. Unfortunately, the debugger does not provide
any information about what is going wrong.

I created an example (for Windows) which shows my errors...

When you click on the treeview node, PD_KLASSE,  you get 1 record in
the DBGrid. The column 'STAM_ID' in the DBgrid does show the value
'1'. I expected to see the value 'stam'. See the attachment. How can I
see 'stam' instead of 1? (1 is the ID field).

then, when i click on an other tree node i get an error. See the
attachment. It has something to do with the dblookupbox but i can not
find it. Has anyone an idea?

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dseligo · 2023-01-17 21:21

Can you provide test data (Planten.db file)?

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Hansvb · 2023-01-21 11:36

Hi,

Attached is the file plants.db
I think I've finally found it. If I create a DBLookupCombobox runtime
with every treeview node change and first destroy the possibly old
one, it seems to work. I need to test some more.
It seems that there remains a relationship between the
DBLookupCombobox and the datasource1/query1 that I cannot find.