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.