superpower
asked on
OnFilterRecord and DBGrid?
Hello, Everyone.
Im using the OnFilterRecord Event on a Paradox Table. Has anyone noticed even though if Filtered=false for the Table, the DBGrid scrolls slower? If I take off the OnFilterRecod event from code,it will go back to normal fast scrolling speed.
Its just weird, when Filtered is set to false it deosn't even goto any line in that event. So why does it become slow? The scrolling is even faster when Filter=true.
So go figure........it should be the other way around. Filtering should make things slower ;-)
Any suggestions are very welcome.
Thanks very much.
P.S
Im using a Table with about 30,000 records.And a Intel P3 1gz, with 256mb ram , and gb's of free disk space. The key is using a very large Table.
If you would like to test , try using a very large
Table . Set the Filtered property to false during design time, and add some commented lines to the OnFilterRecord Event(no real code is needed there , its just to make the event exist) . Now compile and run , you should have the same results.
Im using the OnFilterRecord Event on a Paradox Table. Has anyone noticed even though if Filtered=false for the Table, the DBGrid scrolls slower? If I take off the OnFilterRecod event from code,it will go back to normal fast scrolling speed.
Its just weird, when Filtered is set to false it deosn't even goto any line in that event. So why does it become slow? The scrolling is even faster when Filter=true.
So go figure........it should be the other way around. Filtering should make things slower ;-)
Any suggestions are very welcome.
Thanks very much.
P.S
Im using a Table with about 30,000 records.And a Intel P3 1gz, with 256mb ram , and gb's of free disk space. The key is using a very large Table.
If you would like to test , try using a very large
Table . Set the Filtered property to false during design time, and add some commented lines to the OnFilterRecord Event(no real code is needed there , its just to make the event exist) . Now compile and run , you should have the same results.
kretzschmar
? weird ... listening
Try this to avoid evaluation
Table1.OnFilterRecord := nil;
Best Regards.
Marcos.
Table1.OnFilterRecord := nil;
Best Regards.
Marcos.
ASKER
Hello,
No , I never get to this situation.
Table1.OnFilterRecord := nil;
Any other ideas?
BTW, it isnt as slow if I use a smaller Table. If you would like to test , try using a fairly large Table (more than 1000 records at least), set the Filtered property to false during design time, and only add code the OnFilterRecord Event . Now compile and run , you should have the same results.
Thanks.
No , I never get to this situation.
Table1.OnFilterRecord := nil;
Any other ideas?
BTW, it isnt as slow if I use a smaller Table. If you would like to test , try using a fairly large Table (more than 1000 records at least), set the Filtered property to false during design time, and only add code the OnFilterRecord Event . Now compile and run , you should have the same results.
Thanks.
>you should have the same results
no, i have no difference (maybe my workstation is too fast)
no, i have no difference (maybe my workstation is too fast)
ASKER
P.S
On the other hand, for tests try to use a Table with close enough records to 30,000 just as Im testing with :-)
If you dont have one, you experts know how to make one through a loop .
On the other hand, for tests try to use a Table with close enough records to 30,000 just as Im testing with :-)
If you dont have one, you experts know how to make one through a loop .
Well I just tested with 30,000 records with and without an OnFilterRecord on a Paradox table and there appeared to be no difference in the srolling speed.
PII 450 384MB's RAM Win2000
The Crazy One
PII 450 384MB's RAM Win2000
The Crazy One
ASKER
Hello,
Here is the code I used,just to better illustrate.
unit cfilter;
{Delphi3 Pro, also tried D5}
interface
uses
Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
Grids, DBGrids, Db, DBTables;
type
TForm1 = class(TForm)
Table1: TTable;
{40,000 record table(about 30field Table), Filtered Property is set to false , and Active is set to true during design time}
{same table structure with 8,000 records isnt so harshly
effected}
DataSource1: TDataSource;
DBGrid1: TDBGrid;
procedure Table1FilterRecord(DataSet
private
{ Private declarations }
public
{ Public declarations }
end;
var
Form1: TForm1;
implementation
{$R *.DFM}
procedure TForm1.Table1FilterRecord(
var Accept: Boolean);
begin
{testing lines}
{take comments out and watch how fast the scrolling speed becomes}
end;
end.
Here is the code I used,just to better illustrate.
unit cfilter;
{Delphi3 Pro, also tried D5}
interface
uses
Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
Grids, DBGrids, Db, DBTables;
type
TForm1 = class(TForm)
Table1: TTable;
{40,000 record table(about 30field Table), Filtered Property is set to false , and Active is set to true during design time}
{same table structure with 8,000 records isnt so harshly
effected}
DataSource1: TDataSource;
DBGrid1: TDBGrid;
procedure Table1FilterRecord(DataSet
private
{ Private declarations }
public
{ Public declarations }
end;
var
Form1: TForm1;
implementation
{$R *.DFM}
procedure TForm1.Table1FilterRecord(
var Accept: Boolean);
begin
{testing lines}
{take comments out and watch how fast the scrolling speed becomes}
end;
end.
ASKER
P.S
Problem solved by myself just before I ran out of hope. This was one that really got me stuck.
I found a work around to this bug(It maybe so, or not) , becuase of all the code samples for OnFilterRecord in books, websites that Ive looked at ,had no such mention to do this.
On the OnShow event of the Form I just use
Table1.OnFilterRecord:=nil
It seems Delphi doesn't like that event to be linked , when Filtered=false and some code exists in that event. So I unlink it. And call it back when I want the filtering to start.
Table1.OnFilterRecord := Table1FilterRecord;
Table1.Filtered=true;
But this was a rather tricky one. Becuase anyone trying the code on even a 10,000 record Table wouldnt even seen any difference. It had to be a 30k or 40k record Table with 30fields , in my case.
So do I get those points :-)
Problem solved by myself just before I ran out of hope. This was one that really got me stuck.
I found a work around to this bug(It maybe so, or not) , becuase of all the code samples for OnFilterRecord in books, websites that Ive looked at ,had no such mention to do this.
On the OnShow event of the Form I just use
Table1.OnFilterRecord:=nil
It seems Delphi doesn't like that event to be linked , when Filtered=false and some code exists in that event. So I unlink it. And call it back when I want the filtering to start.
Table1.OnFilterRecord := Table1FilterRecord;
Table1.Filtered=true;
But this was a rather tricky one. Becuase anyone trying the code on even a 10,000 record Table wouldnt even seen any difference. It had to be a 30k or 40k record Table with 30fields , in my case.
So do I get those points :-)
really curious, because i could not reproduce
glad you had it solved yourself
ask at community-support for keep this q
into paq and refunds your points
meikl ;-)
glad you had it solved yourself
ask at community-support for keep this q
into paq and refunds your points
meikl ;-)
ASKER
Thank everyon for trying to help anyway. Still appreciated.
meikl,
But I have one question coming up that maybe you can answer. :-) So il recycle these pionts I get back.
meikl,
But I have one question coming up that maybe you can answer. :-) So il recycle these pionts I get back.
ASKER CERTIFIED SOLUTION
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