Mega Code Archive
Storing Vlaues to the DFM files during design Time
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Title: Storing Vlaues to the DFM files during design Time.
Question: How can I store values in a DFM file during design Time, so that it can be used during run time?
Answer:
Most of use a table or some kind of files to store the data for the
application to pick up the data during run time. Actually we can
store the data in the form file ( dfm ). In the following example I
have created a component derived from the TPersistent class. It uses
the TReader and TWriter class to Read and write to the respective
streams. The TComponentEditor allows
to define the design time editors to work with the component class.
The TPropertyEditor class allows to define a property editor for
a specialized property in a component class.
In the following example I have given the component's source code.
the design time property editor has a source file code(pas) and source form
code for the form (dfm). copy the dfm code to create a dfm file, name it as "propdlg.dfm" and assign it's Name property to "fmpropdlg"
and the source file code to create a pas file, name it as "propdlg.pas". install the component TMyComponent, include the file "propdlg.pas" of the property editor in the the package.
The component will then allow you to invoke the design time editor
by clicking on the object inspector for the specified property
or by right clicking on the component itself and then selecting the
respective verb in the menu context. You can store the fields of the
class Tmydata in the form file ( dfm ) during design time.
//**********************************************************************
//***** Component source (pas) *****************************************
//**********************************************************************
unit Test;
interface
uses
Windows, Forms, Classes, StdCtrls, SysUtils, ComCtrls, Messages, Controls,
{DB, DBCtrls, CommCtrl, OCIH, OCI, OCL, ExtVCs,} dsgnintf;
type
TMyPropertyEditor = class(TPropertyEditor)
private
{ Private declarations }
public
{ Public declarations }
function GetAttributes: TPropertyAttributes; override;
procedure Edit; override;
function GetValue: String; override;
end;
TMyEditorPopup = class(TComponentEditor)
private
{ Private declarations }
public
{ Public declarations }
procedure Edit; override;
procedure ExecuteVerb(Index: Integer); override;
function GetVerb(Index: Integer): String; override;
function GetVerbCount: Integer; override;
end;
TMyData = Class
private
Fstr : String;
FInt : Integer;
public
property StringValue : String Read Fstr Write FStr;
property IntegerValue : Integer Read FInt Write FInt;
end;
TMyTable = Class( TPersistent )
private
FList : TList;
function GetCount : Integer;
function GetItem( Index : Integer ) : TMyData;
Procedure SetItem( Index : Integer; vItem : TMyData );
procedure ReadProperties(Reader: TReader);
procedure WriteProperties(Writer: TWriter);
protected
procedure DefineProperties(Filer: TFiler); override;
public
constructor Create;
destructor Destroy; override;
procedure AddItem;
procedure DeleteItem( Index : Integer );
property ItemCount : Integer Read GetCount;
property Items[Index : Integer] : TMyData Read GetItem Write SetItem; default;
end;
TMyComponent = Class( TComponent )
private
FMyTable : TMyTable;
procedure SetTables( Value : TMyTable );
public
constructor Create(AOwner: TComponent); override;
destructor Destroy; override;
published
property MyTables : TMyTable Read FMyTable Write SetTables;
end;
procedure Register;
implementation
Uses PropDlg;
{ TMyTable }
constructor TMyTable.Create;
begin
FList := TList.Create;
FList.Clear;
end;
destructor TMyTable.Destroy;
begin
FList.Free;
FList := nil;
inherited destroy;
end;
procedure TMyTable.DefineProperties(Filer: TFiler);
begin
Filer.DefineProperty('Tables', ReadProperties, WriteProperties, True);
end;
procedure TMyTable.ReadProperties(Reader: TReader);
begin
Reader.ReadListBegin;
while ( not Reader.EndOfList ) do begin
AddItem;
with Items[itemCount - 1] do begin
Fstr := Reader.ReadString;
FInt := Reader.ReadInteger;
end;
end;
Reader.ReadListEnd;
end;
procedure TMyTable.WriteProperties(Writer: TWriter);
var I : Integer;
begin
Writer.WriteListBegin;
for I := 0 to ( ItemCount - 1 ) do begin
with Items[I] do begin
Writer.WriteString( Fstr );
Writer.WriteInteger( FInt );
end;
end;
Writer.WriteListEnd;
end;
procedure TMyTable.AddItem;
var vData : TMyData;
begin
vData := TMyData.Create;
FList.Add( vData );
end;
function TMyTable.GetCount: Integer;
begin
Result := FList.Count;
end;
function TMyTable.GetItem(Index: Integer): TMyData;
begin
Result := TMyData( FList[ Index ] );
end;
procedure TMyTable.SetItem(Index: Integer; vItem: TMyData);
begin
Flist[ Index ] := vItem;
end;
procedure TMyTable.DeleteItem(Index: Integer);
begin
FList.Delete( Index );
end;
{ TMyComponent }
constructor TMyComponent.Create(AOwner: TComponent);
begin
inherited Create(AOwner);
FMyTable := TMyTable.Create;
end;
destructor TMyComponent.Destroy;
begin
FMyTable.Free;
FMyTable := nil;
inherited Destroy;
end;
procedure TMyComponent.SetTables(Value: TMyTable);
begin
{}
end;
function TMyPropertyEditor.GetAttributes: TPropertyAttributes;
begin
Result:= [paDialog, paReadOnly, paRevertable];
end;
procedure TMyPropertyEditor.Edit;
var
MyComponent: TPersistent;
FMyComponent : TMyComponent;
MyDialog: TfmPropDlg;
begin
MyComponent:= GetComponent(0);
if MyComponent is TMyComponent then
begin
FMyComponent := TMyComponent(MyComponent);
MyDialog := TfmPropDlg.Create(Application);
try
MyDialog.FMyComponent := FMyComponent;
MyDialog.FmyPropertyEditor := Self;
MyDialog.ShowModal;
finally
MyDialog.Free;
MyDialog := nil
end;
end;
end;
function TMyPropertyEditor.GetValue: String;
begin
FmtStr(Result, '(%s)', [GetPropType^.Name]);
end;
procedure Register;
begin
RegisterComponents('YOGI',[TMyComponent]);
RegisterPropertyEditor(TypeInfo(TMyTable), TMyComponent, 'MyTables',TMyPropertyEditor);
RegisterComponentEditor(TMyComponent, TMyEditorPopup);
end;
{ TMyEditorPopup }
procedure TMyEditorPopup.Edit;
var
// MyComponent : TPersistent;
FMyComponent : TMyComponent;
MyDialog: TfmPropDlg;
begin
if Component is TMyComponent then
begin
FMyComponent := TMyComponent( Component );
MyDialog:= TfmPropDlg.Create(Application);
try
MyDialog.FMyComponent := FMyComponent;
MyDialog.FMyEditorPopup := Self;
MyDialog.ShowModal;
finally
MyDialog.Free;
MyDialog := nil;
end;
end;
end;
procedure TMyEditorPopup.ExecuteVerb(Index: Integer);
begin
if ( Index = 0 ) then Edit;
end;
function TMyEditorPopup.GetVerb(Index: Integer): String;
begin
if Index = 0 then
Result:= 'Yoganand''s Editor';
end;
function TMyEditorPopup.GetVerbCount: Integer;
begin
Result:= 1;
end;
{ TMyTest }
end.
//**********************************************************************
//***** Property Editor's source file (pas) code *******************
//**********************************************************************
unit propDlg;
interface
uses
Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
Buttons, StdCtrls, Test, dsgnintf;
type
TfmPropDlg = class(TForm)
Label1: TLabel;
Label2: TLabel;
edtStr: TEdit;
edtInt: TEdit;
sbAdd: TSpeedButton;
sbDelete: TSpeedButton;
sbOk: TSpeedButton;
sbCancel: TSpeedButton;
sbup: TSpeedButton;
sbDown: TSpeedButton;
procedure sbAddClick(Sender: TObject);
procedure sbOkClick(Sender: TObject);
procedure sbupClick(Sender: TObject);
procedure FormCreate(Sender: TObject);
procedure FormShow(Sender: TObject);
procedure sbDownClick(Sender: TObject);
procedure sbDeleteClick(Sender: TObject);
private
{ Private declarations }
FCurrentIndex : Integer;
public
{ Public declarations }
FMyComponent : TMyComponent ;
FMyPropertyEditor: TPropertyEditor;
FMyEditorPopup: TComponentEditor;
FPageIndex: Integer;
end;
var
fmPropDlg: TfmPropDlg;
implementation
{$R *.DFM}
procedure TfmPropDlg.sbAddClick(Sender: TObject);
begin
FMyComponent.MyTables.AddItem;
edtStr.Text := '';
edtInt.Text := '';
edtStr.SetFocus;
end;
procedure TfmPropDlg.sbOkClick(Sender: TObject);
begin
FMyComponent.MyTables[ FMyComponent.MyTables.ItemCount - 1 ].StringValue := edtStr.Text;
FMyComponent.MyTables[ FMyComponent.MyTables.ItemCount - 1 ].IntegerValue := StrtoInt(edtInt.Text);
end;
procedure TfmPropDlg.sbupClick(Sender: TObject);
var I : Integer;
begin
if ( FCurrentIndex 0 ) then begin
Dec( FCurrentIndex );
edtStr.Text := FMyComponent.MyTables[ FCurrentIndex ].StringValue;
edtInt.Text := Inttostr( FMyComponent.MyTables[ FCurrentIndex].IntegerValue );
end;
end;
procedure TfmPropDlg.FormCreate(Sender: TObject);
begin
FCurrentIndex := 0;
end;
procedure TfmPropDlg.FormShow(Sender: TObject);
begin
if ( FMyComponent.MyTables.ItemCount 0 ) then begin
FCurrentIndex := 0;
edtStr.Text := FMyComponent.MyTables[ FCurrentIndex ].StringValue;
edtInt.Text := Inttostr( FMyComponent.MyTables[ FCurrentIndex].IntegerValue );
end;
end;
procedure TfmPropDlg.sbDownClick(Sender: TObject);
begin
if ( FCurrentIndex Inc( FCurrentIndex );
edtStr.Text := FMyComponent.MyTables[ FCurrentIndex ].StringValue;
edtInt.Text := Inttostr( FMyComponent.MyTables[ FCurrentIndex].IntegerValue );
end;
end;
procedure TfmPropDlg.sbDeleteClick(Sender: TObject);
begin
if ( FMyComponent.MyTables.ItemCount 0 ) then begin
FMyComponent.MyTables.DeleteItem( FCurrentIndex );
FCurrentIndex := 0;
edtStr.Text := FMyComponent.MyTables[ FCurrentIndex ].StringValue;
edtInt.Text := Inttostr( FMyComponent.MyTables[ FCurrentIndex].IntegerValue );
end;
end;
end.
//**********************************************************************
//****** Property Editor's form file (dfm) Code **************************
//**********************************************************************
object fmPropDlg: TfmPropDlg
Left = 263
Top = 371
BorderStyle = bsDialog
Caption = 'Editor Dlg'
ClientHeight = 103
ClientWidth = 218
Color = clBtnFace
Font.Charset = DEFAULT_CHARSET
Font.Color = clWindowText
Font.Height = -11
Font.Name = 'MS Sans Serif'
Font.Style = []
OldCreateOrder = False
Position = poScreenCenter
OnCreate = FormCreate
OnShow = FormShow
PixelsPerInch = 96
TextHeight = 13
object Label1: TLabel
Left = 16
Top = 24
Width = 36
Height = 13
Caption = 'Value 1'
end
object Label2: TLabel
Left = 17
Top = 51
Width = 33
Height = 13
Caption = 'Value2'
end
object sbAdd: TSpeedButton
Left = 26
Top = 77
Width = 23
Height = 22
Glyph.Data = {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}
NumGlyphs = 2
OnClick = sbAddClick
end
object sbDelete: TSpeedButton
Left = 62
Top = 76
Width = 23
Height = 22
Glyph.Data = {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}
NumGlyphs = 2
OnClick = sbDeleteClick
end
object sbOk: TSpeedButton
Left = 100
Top = 76
Width = 23
Height = 22
Glyph.Data = {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}
NumGlyphs = 2
OnClick = sbOkClick
end
object sbCancel: TSpeedButton
Left = 144
Top = 76
Width = 23
Height = 22
Glyph.Data = {
76010000424D7601000000000000760000002800000020000000100000000100
04000000000000010000130B0000130B00001000000000000000000000000000
800000800000008080008000000080008000808000007F7F7F00BFBFBF000000
FF0000FF000000FFFF00FF000000FF00FF00FFFF0000FFFFFF00333333333333
333333333333333333333333333333333333333FFF33FF333FFF339993370733
999333777FF37FF377733339993000399933333777F777F77733333399970799
93333333777F7377733333333999399933333333377737773333333333990993
3333333333737F73333333333331013333333333333777FF3333333333910193
333333333337773FF3333333399000993333333337377737FF33333399900099
93333333773777377FF333399930003999333337773777F777FF339993370733
9993337773337333777333333333333333333333333333333333333333333333
3333333333333333333333333333333333333333333333333333}
NumGlyphs = 2
end
object sbup: TSpeedButton
Left = 192
Top = 16
Width = 23
Height = 22
Glyph.Data = {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}
NumGlyphs = 2
OnClick = sbupClick
end
object sbDown: TSpeedButton
Left = 192
Top = 64
Width = 23
Height = 22
Glyph.Data = {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}
NumGlyphs = 2
OnClick = sbDownClick
end
object edtStr: TEdit
Left = 56
Top = 21
Width = 121
Height = 21
TabOrder = 0
end
object edtInt: TEdit
Left = 56
Top = 48
Width = 121
Height = 21
TabOrder = 1
end
end
//******************************************************
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