关于 Delphi 中流的使用(5) 组件序列化

unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls;

type
  TForm1 = class(TForm)
    Button1: TButton;
    Button2: TButton;
    Button3: TButton;
    Button4: TButton;
    Memo1: TMemo;
    procedure Button1Click(Sender: TObject);
    procedure Button2Click(Sender: TObject);
    procedure Button3Click(Sender: TObject);
    procedure Button4Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

//添加一个 Memo1 然后修改其内容
procedure TForm1.Button1Click(Sender: TObject);
begin
  WriteComponentResFile('c:\temp\memo.dat', Memo1);
  {只此一句就可以把当前的 Memo 的状态序列化到文件}
end;


//反序列化, 读回
procedure TForm1.Button2Click(Sender: TObject);
begin
  ReadComponentResFile('c:\temp\memo.dat', Memo1);
  {一句话就可以读回, 不管是经过了什么操作(甚至是关机)}
end;


{
  这好像和流没什么关系, 其实这就是流的典型操作,
  WriteComponentResFile 和 ReadComponentResFile 分别调用了流类的
  WriteComponentRes 与 ReadComponentRes 方法.
  下面用更直接的流的方式重新实现一次:
}


//序列化
procedure TForm1.Button3Click(Sender: TObject);
var
  stream: TStream;
const
  strPath = 'c:\temp\m.dat';
begin
  stream := TFileStream.Create(strPath, fmCreate);
  stream.WriteComponentRes(Memo1.ClassName, Memo1);
  {WriteComponentRes 有两个参数: 文件名和组件名}
  stream.Free;
end;


//反序列化
procedure TForm1.Button4Click(Sender: TObject);
var
  stream: TStream;
const
  strPath = 'c:\temp\m.dat';
begin
  stream := TFileStream.Create(strPath, fmOpenRead);
  stream.ReadComponentRes(Memo1);
  {ReadComponentRes 只有一个参数: 组件名}
  stream.Free;
end;

end.