delphi 2009 中 TStrings 与 TStream 的增强

在 Delphi 2009 中,

TStrings 类(包括 TStringList 和包含 TStrings 属性的所有组件, 譬如 Memo.lines 属性、ListBox.Items 属性)、

TStream 类系列(包括 TFileStream、TMemoryStream 等) 的存取方法, 譬如:

LoadFromFile、SaveToFile、LoadFromStream、SaveToStream, 都有了选择 TEncoding 参数的重载.

本例效果图:

代码文件:

unit Unit1;

interface

uses

Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,

Dialogs, StdCtrls;

type

TForm1 = class(TForm)

Memo1: TMemo;

Memo2: TMemo;

Button1: TButton;

Button2: TButton;

Button3: TButton;

Button4: TButton;

Button5: TButton;

Button6: TButton;

Button7: TButton;

Button8: TButton;

Button9: TButton;

procedure FormCreate(Sender: TObject);

procedure Button1Click(Sender: TObject);

procedure Button2Click(Sender: TObject);

procedure Button3Click(Sender: TObject);

procedure Button4Click(Sender: TObject);

procedure Button5Click(Sender: TObject);

procedure Button6Click(Sender: TObject);

procedure Button7Click(Sender: TObject);

procedure Button8Click(Sender: TObject);

procedure Button9Click(Sender: TObject);

end;

var

Form1: TForm1;

implementation

{$R *.dfm}

const

FilePath = 'c:\temp\test.txt';

var

str: string;

procedure TForm1.FormCreate(Sender: TObject);

begin

Memo1.ReadOnly := True;

str := Memo1.Text;

Button1.Caption := 'TStrings 默认存取';

Button2.Caption := 'TStrings ASCII 存取';

Button3.Caption := 'TStrings UTF8 存取';

Button4.Caption := 'TFileStream 默认存取';

Button5.Caption := 'TFileStream ASCII 存取';

Button6.Caption := 'TFileStream UTF8存取';

Button7.Caption := 'TMemoryStream 默认存取';

Button8.Caption := 'TMemoryStream ASCII 存取';

Button9.Caption := 'TMemoryStream UTF8 存取';

end;

procedure TForm1.Button1Click(Sender: TObject);

var

List: TStrings;

begin

List := TStringList.Create;

List.Text := str;

List.SaveToFile(FilePath);

List.LoadFromFile(FilePath);

Memo2.Lines := List;

List.Free;

end;

procedure TForm1.Button2Click(Sender: TObject);

var

List: TStrings;

begin

List := TStringList.Create;

List.Text := str;

List.SaveToFile(FilePath, TEncoding.ASCII);

List.LoadFromFile(FilePath, TEncoding.ASCII);

Memo2.Lines := List;

List.Free;

end;

procedure TForm1.Button3Click(Sender: TObject);

var

List: TStrings;

begin

List := TStringList.Create;

List.Text := str;

List.SaveToFile(FilePath, TEncoding.UTF8);

List.LoadFromFile(FilePath, TEncoding.UTF8);

Memo2.Lines := List;

List.Free;

end;

procedure TForm1.Button4Click(Sender: TObject);

var

stream: TStream;

begin

stream := TFileStream.Create(FilePath, fmCreate);

Memo1.Lines.SaveToStream(stream);

stream.Position := 0;

Memo2.Lines.LoadFromStream(stream);

stream.Free;

end;

procedure TForm1.Button5Click(Sender: TObject);

var

stream: TStream;

begin

stream := TFileStream.Create(FilePath, fmCreate);

Memo1.Lines.SaveToStream(stream, TEncoding.ASCII);

stream.Position := 0;

Memo2.Lines.LoadFromStream(stream, TEncoding.ASCII);

stream.Free;

end;

procedure TForm1.Button6Click(Sender: TObject);

var

stream: TStream;

begin

stream := TFileStream.Create(FilePath, fmCreate);

Memo1.Lines.SaveToStream(stream, TEncoding.UTF8);

stream.Position := 0;

Memo2.Lines.LoadFromStream(stream, TEncoding.UTF8);

stream.Free;

end;

procedure TForm1.Button7Click(Sender: TObject);

var

stream: TMemoryStream;

begin

stream := TMemoryStream.Create;

Memo1.Lines.SaveToStream(stream);

stream.SaveToFile(FilePath);

stream.LoadFromFile(FilePath);

stream.Position := 0;

Memo2.Lines.LoadFromStream(stream);

stream.Free;

end;

procedure TForm1.Button8Click(Sender: TObject);

var

stream: TMemoryStream;

begin

stream := TMemoryStream.Create;

Memo1.Lines.SaveToStream(stream, TEncoding.ASCII);

stream.SaveToFile(FilePath);

stream.LoadFromFile(FilePath);

stream.Position := 0;

Memo2.Lines.LoadFromStream(stream, TEncoding.ASCII);

stream.Free;

end;

procedure TForm1.Button9Click(Sender: TObject);

var

stream: TMemoryStream;

begin

stream := TMemoryStream.Create;

Memo1.Lines.SaveToStream(stream, TEncoding.UTF8);

stream.SaveToFile(FilePath);

stream.LoadFromFile(FilePath);

stream.Position := 0;

Memo2.Lines.LoadFromStream(stream, TEncoding.UTF8);

stream.Free;

end;

end.

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