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{*****************************************}
{ }
{ FastReport v2.3 }
{ Report dataset }
{ }
{ Copyright (c) 1998-99 by Tzyganenko A. }
{ }
{*****************************************}
unit LR_DSet;
interface
{$I LR_Vers.inc}
uses
SysUtils, Classes;
type
TRangeBegin = (rbFirst, rbCurrent);
TRangeEnd = (reLast, reCurrent, reCount);
TCheckEOFEvent = procedure(Sender: TObject; var Eof: Boolean) of object;
{ TfrDataset }
TfrDataset = class(TComponent)
protected
FRangeBegin: TRangeBegin;
FRangeEnd: TRangeEnd;
FRangeEndCount: Integer;
FOnFirst, FOnNext, FOnLast: TNotifyEvent;
FOnCheckEOF: TCheckEOFEvent;
FRecNo: Integer;
procedure DoCheckEOF(var Eof: Boolean); virtual;
procedure DoFirst; virtual;
procedure DoNext; virtual;
public
constructor Create(AOwner: TComponent); override;
procedure Init; virtual;
procedure Exit; virtual;
procedure First; virtual;
procedure Next; virtual;
procedure Refresh; virtual;
function GetBookMark : Pointer; virtual;
procedure GotoBookMark({%H-}BM : Pointer); virtual;
procedure FreeBookMark({%H-}BM : Pointer); virtual;
procedure DisableControls; virtual;
procedure EnableControls; virtual;
function Eof: Boolean; virtual;
property RangeBegin: TRangeBegin read FRangeBegin write FRangeBegin default rbFirst;
property RangeEnd: TRangeEnd read FRangeEnd write FRangeEnd default reLast;
property RangeEndCount: Integer read FRangeEndCount write FRangeEndCount default 0;
property RecNo: Integer read FRecNo;
property OnCheckEOF: TCheckEOFEvent read FOnCheckEOF write FOnCheckEOF;
property OnFirst: TNotifyEvent read FOnFirst write FOnFirst;
property OnNext: TNotifyEvent read FOnNext write FOnNext;
end;
TfrUserDataset = class(TfrDataset)
published
property RangeBegin;
property RangeEnd;
property RangeEndCount;
property OnCheckEOF;
property OnFirst;
property OnNext;
end;
implementation
procedure TfrDataset.DoCheckEOF(var Eof: Boolean);
begin
if Assigned(FOnCheckEOF) then
FOnCheckEOF(Self, Eof);
end;
procedure TfrDataset.DoFirst;
begin
if Assigned(FOnFirst) then
FOnFirst(Self);
end;
procedure TfrDataset.DoNext;
begin
if Assigned(FOnNext) then
FOnNext(Self);
end;
constructor TfrDataSet.Create(AOwner: TComponent);
begin
inherited Create(AOwner);
RangeBegin := rbFirst;
RangeEnd := reLast;
end;
procedure TfrDataSet.Init;
begin
end;
procedure TfrDataSet.Exit;
begin
end;
procedure TfrDataSet.First;
begin
FRecNo := 0;
DoFirst;
end;
procedure TfrDataSet.Next;
begin
Inc(FRecNo);
DoNext;
end;
procedure TfrDataset.Refresh;
begin
end;
function TfrDataset.GetBookMark: Pointer;
begin
Result:=nil;
end;
procedure TfrDataset.GotoBookMark(BM: Pointer);
begin
end;
procedure TfrDataset.FreeBookMark(BM: Pointer);
begin
end;
procedure TfrDataset.DisableControls;
begin
end;
procedure TfrDataset.EnableControls;
begin
end;
function TfrDataSet.Eof: Boolean;
begin
Result := False;
if (FRangeEnd = reCount) and (FRecNo >= FRangeEndCount) then
Result := True;
DoCheckEOF(Result);
end;
end.
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