Mega Code Archive
Streaming Components
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Title: Streaming Components
Question: Saving and loading Component Published Propertys to disk
Answer:
The TStreams Class has a nice feature Couse it can stream component propertys in just one line .
So here's the complete unit where i Stream the component
If your class is not in the same unit you will have to register it .
{
procedure RegisterClasses(AClasses: array of TPersistentClass);
Description
Call RegisterClasses to register a set of custom classes in a single line. Each class is registered by calling RegisterClass. Unregistered classes cant be loaded or saved by the VCL streaming system.
}
unit Unit1;
interface
uses
Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
StdCtrls;
type
// jus a enumeration
TSomeints = 1..10 ;
// set of the enumeration
TExampleSet = Set of TSomeints;
TExampleComponent = Class(TComponent)
private
FASet: TExampleSet;
FAString: String;
FAFloat: Double;
FAInteger: Integer;
published
// Anyting you want streamed and is streameble by Delphi you can publish
// as property
Property AString : String read FAString write FAString;
Property ASet : TExampleSet read FASet write FASet;
Property AInteger : Integer read FAInteger write FAInteger;
Property AFloat : Double read FAFloat write FAFloat;
end;
TForm1 = class(TForm)
SaveToStream: TButton;
LoadFromStream: TButton;
OpenDialog1: TOpenDialog;
SaveDialog1: TSaveDialog;
EAFloat: TEdit;
EAstring: TEdit;
procedure SaveToStreamClick(Sender: TObject);
procedure FormCreate(Sender: TObject);
procedure FormDestroy(Sender: TObject);
procedure LoadFromStreamClick(Sender: TObject);
private
FExampleComponent: TExampleComponent;
procedure SetExampleComponent(const Value: TExampleComponent);
{ Private declarations }
public
Property ExampleComponent : TExampleComponent read FExampleComponent write SetExampleComponent;
Procedure ObjectToGui ;
Procedure GuiToObject ;
{ Public declarations }
end;
var
Form1: TForm1;
implementation
{$R *.DFM}
procedure TForm1.SaveToStreamClick(Sender: TObject);
var
AStream : TMemoryStream ;
begin
IF SaveDialog1.execute then
begin
GuiToObject ;
AStream := TMemoryStream.Create ;
try
AStream.WriteComponent(ExampleComponent);
AStream.SaveToFile(SaveDialog1.FileName);
finally
AStream.free ;
end;
end;
end;
procedure TForm1.SetExampleComponent(const Value: TExampleComponent);
begin
FExampleComponent := Value;
end;
procedure TForm1.FormCreate(Sender: TObject);
begin
// this is the Procedure To Call if you want to Use components not defined
// in this unit ;
// RegisterClasses([TButton,TMemo,TEnz]);
FExampleComponent := TExampleComponent.Create(Self);
end;
procedure TForm1.FormDestroy(Sender: TObject);
begin
FExampleComponent.free ;
end;
procedure TForm1.LoadFromStreamClick(Sender: TObject);
var
AStream : TMemoryStream ;
begin
IF OpenDialog1.execute then
begin
AStream := TMemoryStream.Create ;
try
AStream.LoadFromFile(OpenDialog1.FileName);
AStream.ReadComponent(ExampleComponent);
ObjectToGui ;
finally
AStream.free ;
end;
end;
end;
procedure TForm1.GuiToObject;
begin
ExampleComponent.AString := EAstring.Text ;
ExampleComponent.AFloat := StrToFloat(EAFloat.Text) ;
end;
procedure TForm1.ObjectToGui;
begin
EAstring.Text := ExampleComponent.AString ;
EAFloat.Text := FloatToStr(ExampleComponent.AFloat) ;
end;
end.
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