Finding the key from TDBLookupComboBox Selection
lazarus / 16-Databases

----------------------------------------------------------------------
jack · 2012-02-04 17:09

I have been digging for several hours trying to understand how I might
retrieve the key from the field selected in a TDBLookupComboBox.

I have the field data from the caption but cannot figure out how to
get the key to that field.

If anyone could help, perhaps with an example??

----------------------------------------------------------------------
LuizAmérico · 2012-02-04 17:17

TDBLookupComboBox.KeyValue

----------------------------------------------------------------------
jack · 2012-02-04 21:19

Thank You, I looked  and looked and did not see.

----------------------------------------------------------------------
jack · 2012-02-05 03:29

I was having fits with this until I realized that the KeyValue was not
always being returned, sometimes it is null which throws an
exception.  This turns out to be because I had not identified the
primary key field in the TSQLQuery.  I did not because I never
intended to write to the database.  Apparently the TDBLookuoComboBox
somehow needs to know the primary key also.

To fix this I Double click on the TSQLQuery and adding all the fields
in the popup box (click the plus sign - hint: if the plus sign does
not produce a list of fields then the query is inactive).  Then select
the field that is the table primaty key and in the properties window,
set the providerFlags[pfinkey] to true. This established the primary
key and fixed my problem with nulls coming back as the KeyValue.

Thanks again to all who have been answering my questions along the
way!!!