126 lines
2.9 KiB
ObjectPascal
126 lines
2.9 KiB
ObjectPascal
unit JvDBCheckBox;
|
|
|
|
interface
|
|
|
|
uses
|
|
Windows, Messages, SysUtils, Classes, Contnrs, Controls, DB, DBCtrls;
|
|
|
|
type
|
|
TJvDBCheckBoxChangingEvent = procedure(Sender: TObject; var Allow: Boolean) of object;
|
|
|
|
TJvDBCheckBox = class(TDBCheckBox)
|
|
private
|
|
FDirectEdit: Boolean;
|
|
FOnChange: TNotifyEvent;
|
|
FOnChanging: TJvDBCheckBoxChangingEvent;
|
|
FOrgDataChange: TNotifyEvent;
|
|
FDataChanging: Integer;
|
|
FToggling: Integer;
|
|
FOldValue: Variant;
|
|
|
|
procedure CMExit(var Message: TCMExit); message CM_EXIT;
|
|
function GetDataLink: TFieldDataLink;
|
|
protected
|
|
procedure DataChange(Sender: TObject);
|
|
|
|
procedure Toggle; override;
|
|
function DoChanging: Boolean; virtual;
|
|
procedure DoChange; virtual;
|
|
procedure KeyPress(var Key: Char); override;
|
|
public
|
|
constructor Create(AOwner: TComponent); override;
|
|
published
|
|
property DirectEdit: Boolean read FDirectEdit write FDirectEdit default True;
|
|
property OnChanging: TJvDBCheckBoxChangingEvent read FOnChanging write FOnChanging;
|
|
property OnChange: TNotifyEvent read FOnChange write FOnChange;
|
|
end;
|
|
|
|
implementation
|
|
|
|
{ TJvDBCheckBox }
|
|
|
|
constructor TJvDBCheckBox.Create(AOwner: TComponent);
|
|
begin
|
|
inherited Create(AOwner);
|
|
FDirectEdit := True;
|
|
FOrgDataChange := GetDataLink.OnDataChange;
|
|
GetDataLink.OnDataChange := DataChange;
|
|
end;
|
|
|
|
procedure TJvDBCheckBox.CMExit(var Message: TCMExit);
|
|
begin
|
|
if DirectEdit then
|
|
begin
|
|
if GetDataLink.Active and (Field <> nil) then
|
|
FOldValue := Field.Value;
|
|
DoExit // TWinControl behaviour
|
|
end
|
|
else
|
|
inherited;
|
|
end;
|
|
|
|
procedure TJvDBCheckBox.DoChange;
|
|
begin
|
|
if Assigned(FOnChange) then
|
|
FOnChange(Self);
|
|
end;
|
|
|
|
procedure TJvDBCheckBox.Toggle;
|
|
begin
|
|
if FDataChanging = 0 then
|
|
begin
|
|
if not DoChanging then
|
|
Exit;
|
|
end;
|
|
|
|
Inc(FToggling);
|
|
try
|
|
inherited Toggle;
|
|
if DirectEdit and (FDataChanging = 0) and GetDataLink.Active and GetDataLink.Editing then
|
|
GetDataLink.UpdateRecord;
|
|
finally
|
|
Dec(FToggling);
|
|
end;
|
|
|
|
if FDataChanging = 0 then
|
|
DoChange;
|
|
end;
|
|
|
|
function TJvDBCheckBox.DoChanging: Boolean;
|
|
begin
|
|
Result := True;
|
|
if Assigned(FOnChanging) then
|
|
FOnChanging(Self, Result);
|
|
end;
|
|
|
|
function TJvDBCheckBox.GetDataLink: TFieldDataLink;
|
|
begin
|
|
Result := TFieldDataLink(Perform(CM_GETDATALINK, 0, 0));
|
|
end;
|
|
|
|
procedure TJvDBCheckBox.KeyPress(var Key: Char);
|
|
begin
|
|
case Key of
|
|
#27:
|
|
if (Field <> nil) and (DataSource <> nil) and (DataSource.State in [dsEdit, dsInsert]) then
|
|
Field.Value := FOldValue;
|
|
end;
|
|
inherited KeyPress(Key);
|
|
end;
|
|
|
|
procedure TJvDBCheckBox.DataChange(Sender: TObject);
|
|
begin
|
|
if (FToggling = 0) and DirectEdit and (Field <> nil) then
|
|
FOldValue := Field.Value;
|
|
|
|
Inc(FDataChanging);
|
|
try
|
|
FOrgDataChange(Sender);
|
|
finally
|
|
Dec(FDataChanging);
|
|
end;
|
|
end;
|
|
|
|
end.
|
|
|