🚀 go-pugleaf

On 22 Aug 2002 01:40:45 -0700, "Gareth" <gbh_2@hotmail.com> wrote:

>
>I am fairly new to c++ programming so this maybe an easily solved problem.  
>The thing is i have my DBLookupComboBox linked to a database and if i 
>click on the down arrow it does display al of the items in the table but 
>when i first load the program the field is blank but i want it to automatically 
>display the first record in the table.  This problem also arises when i delete 
>the currently selected record because it leaves the old value in the 
>combo box even though the item is deleted, so i then have to manually 
>select a different item in it.  This is very sloppy the way it is and require 
>help to fix it.

Hi Gareth,

    you have to set TDBLookupComboBox::KeyValue when you are opening the
associated dataset, or when the linked TDataSource's OnDataChange event
handler is fired. Try with something like the following code:  

void __fastcall TForm1::DataSource1DataChange(TObject *Sender,
      TField *Field)
{
    const AnsiString KeyField( DBLookupComboBox1->KeyField );
    TDataSource& DataSource( *DBLookupComboBox1->ListSource );
    TDataSet& DataSet( *DataSource.DataSet );
    DBLookupComboBox1->KeyValue = DataSet.FieldByName( KeyField )->Value;
}

Hope this helps.

Ciao!

Giuliano