(09/2015) I just jumped from D6 to XE8. Having a number of issues. Including this TProgressBar thing. Tabled it for a while. Came across this (Erik Knowles) fix tonight. Fantastic. Except: the first scenario I ran through had a Max value of 9,770,880. And it (Erik Knowles' "original" fix) REALLY added to the time this process took (with all the extra actual updating of the ProgressBar).
So I expanded his class to reduce the amount of times the ProgressBar actually redraws itself. But ONLY IF the "original" Max value is greater than MIN_TO_REWORK_PCTS (I settled on 5000 here).
If so, the ProgressBar only updates itself HUNDO times (here I started with and pretty much settled on 100, hence the "HUNDO" name).
I accounted for some quirkiness at the Max value as well:
if Abs(FOriginalMax - value) <= 1 then
pct := HUNDO
I tested this against my original 9.8m Max. And, with this standalone test app:
:
uses
:
ProgressBarFix;
const
PROGRESS_PTS = 500001;
type
TForm1 = class(TForm)
Label1: TLabel;
PB: TProgressBar;
Button1: TButton;
procedure Button1Click(Sender: TObject);
end;
var
Form1: TForm1;
implementation
{$R *.dfm}
procedure TForm1.Button1Click(Sender: TObject);
var
x: integer;
begin
PB.Min := 0;
PB.Max := PROGRESS_PTS;
PB.Position := 0;
for x := 1 to PROGRESS_PTS do
begin
//let's do something
//
Label1.Caption := Format('%d of %d',[x,PROGRESS_PTS]);
Update;
PB.Position := x;
end;
PB.Position := 0;
end;
end.
with PROGRESS_PTS values of:
10
100
1,000
10,000
100,000
1,000,000
It's smooth and "accurate" for all of these values - without really slowing anything down.
In testing, I was able to toggle my compiler directive DEF_USE_MY_PROGRESS_BAR to test both ways (this TProgressBar replacement vs the original).
Note that you might want to uncomment the call to Application.ProcessMessages.
Here is the (my "enhanced") ProgressBarFix source:
unit ProgressBarFix;
interface
uses
Vcl.ComCtrls;
type
TProgressBar = class(Vcl.ComCtrls.TProgressBar)
const
HUNDO = 100;
MIN_TO_REWORK_PCTS = 5000;
private
function GetMax: integer;
procedure SetMax(value: integer);
function GetPosition: integer;
procedure SetPosition(value: integer);
published
property Max: integer read GetMax write SetMax default 100;
property Position: integer read GetPosition write SetPosition default 0;
private
FReworkingPcts: boolean;
FOriginalMax: integer;
FLastPct: integer;
end;
implementation
function TProgressBar.GetMax: integer;
begin
result := inherited Max;
end;
procedure TProgressBar.SetMax(value: integer);
begin
FOriginalMax := value;
FLastPct := 0;
FReworkingPcts := FOriginalMax > MIN_TO_REWORK_PCTS;
if FReworkingPcts then
inherited Max := HUNDO
else
inherited Max := value;
end;
function TProgressBar.GetPosition: integer;
begin
result := inherited Position;
end;
procedure TProgressBar.SetPosition(value: integer);
var
pct: integer;
begin
//Application.ProcessMessages;
if value = inherited Position then
exit;
if FReworkingPcts then
begin
if Abs(FOriginalMax - value) <= 1 then
pct := HUNDO
else
pct := Trunc((value / FOriginalMax) * HUNDO);
if pct = FLastPct then
exit;
FLastPct := pct;
value := pct;
end;
if value < Max then
begin
inherited Position := Succ(value);
inherited Position := value;
end
else
begin
Max := Succ(Max);
inherited Position := Max;
inherited Position := value;
Max := Pred(Max);
end;
end;
end.
