cancel during asyncfetchnonblocking

From: Lutz Kutscher (imnot_at_home.de)
Date: 08/17/04 

Date: Tue, 17 Aug 2004 21:27:44 +0200

Hi,

I wanted to use the ExecuteOption eoAsyncFetchNonBlocking to build a
progressive filtering form:

In the OnShow event of my form I open a query on a large table
(20,000+ records):
"select * from HugeTable"

Since it is opened in non blocking mode, the user can enter a search
string into a TEdit control.
The OnChange of that TEdit looks like this:

TMyForm.Edit1Change(Sender: TObject);
begin
        AdoDS.Close;
        AdoDS.CommandText := 'select * from HugeTable where SearchField='''
+ Edit1.Text + '''';
        AdoDS.Open;
end;

The problem with this seems to be, that the query is not really cancelled
with the
AdoDS.Close - looking at my memory usage it climbs incredibly.

I tried using the OnFetchProgress event to set EventStatus to esCancel
- the name and declaration as var parameter sounded like it could work -
nothing.

Can anyone around here tell me, how to really tell ADO to stop loading the
data that isn't needed any longer?

Thanks a lot
Lutz