DBLookUpComboBox and 'invalid variant type cast'
lazarus / 16-Databases

----------------------------------------------------------------------
rise_nak · 2011-06-16 20:03

Hello,
I'm trying to use DBLookUpComboBox to make something like a filter for
a DBGrid.
I put DBLookUpComboBox1 on the form and on buttonclick I have the
following code:

Code: [Select]DBLookupComboBox1.DataSource := FormKraj.DataListaWalut;
  DBLookupComboBox1.DataField := 'SYMBOL_I_PANSTWO';
  DBLookupComboBox1.ListSource := FormKraj.DataListaWalut;
  DBLookupComboBox1.ListField := 'SYMBOL_I_PANSTWO';
  DBLookupComboBox1.KeyField := 'WAL_ID';
ListaWalutQuery.Open;

ListaWalutQuery is connected with DataListaWalut datasource.
I have also DGGrid with DataSource := DataListaWalut and everything is
ok, so I think that a problem is somewhere in  DBLookupComboBox.
When I click button I got an error 'invalid variant type cast' ,
debugger shows that a problem is in function TDBLookup.ListFieldValue.
Than I got an error 'invalid value for field 'WAL_iD'' and debugger
shows the same line.
List is filled by values from field SYMBOL_I_PANSTWO, as it should,
but when I choose a position from list I  got the same error 'invalid
variant type cast' and 'invalid value for field 'WAL_iD''.

Code: [Select]ListaWalutQuery.SQL := 'SELECT a.*, a.WAL_SYMBOL||' -
'||a.WAL_PANSTWO as SYMBOL_I_PANSTWO FROM WALUTY_TABELE a;'

What an i doing wrong?

----------------------------------------------------------------------
woffleys · 2011-12-30 14:11

I have had the same problem, however, I have made a change to the code
in dblookup.inc to fix this. if its not fixed, change

'VarArrayOf([AListFieldValue])' to 'AListFieldValue'

in

procedure TDBLookup.UpdateData(const AListFieldValue: string);

around line 392