Delphi 2009 之 TStringBuilder 类[2]: Append 与 AppendFormat

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;
Button5: TButton;
procedure Button1Click(Sender: TObject);
procedure Button2Click(Sender: TObject);
procedure Button3Click(Sender: TObject);
procedure Button4Click(Sender: TObject);
procedure Button5Click(Sender: TObject);
end;

var
Form1: TForm1;

implementation

{$R *.dfm}

//TStringBuilder.Append 可以添加几乎所有数据类型, 甚至是对象
procedure TForm1.Button1Click(Sender: TObject);
var
sb1,sb2: TStringBuilder;
ver: Cardinal;
begin
sb1 := TStringBuilder.Create;
sb2 := TStringBuilder.Create;

sb1.Append('Delphi ');
ver := 2009;
sb1.Append(ver);
ShowMessage(sb1.ToString); {Delphi 2009}

sb2.Append(sb1);
{换行}
sb2.AppendLine;
sb2.Append(Self);
ShowMessage(sb2.ToString); {Delphi 2009
TForm1}

sb1.Free;
sb2.Free;
end;

//TStringBuilder.Append 截取字符数组和字符串
procedure TForm1.Button2Click(Sender: TObject);
const
CharArr: array[0..6] of Char = ('A','B','C','D','E','F','G');
Str = 'ABCDEFG';
var
sb: TStringBuilder;
begin
sb := TStringBuilder.Create;
sb.Append(CharArr, 2, 3);
ShowMessage(sb.ToString); {CDE}

{清空}
sb.Length := 0;

sb.Append(Str, 2, 3);
ShowMessage(sb.ToString); {CDE}

sb.Free;
end;

//TStringBuilder.Append 添加指定数目的字符
procedure TForm1.Button3Click(Sender: TObject);
var
sb: TStringBuilder;
begin
sb := TStringBuilder.Create;
sb.Append('A', 10);
ShowMessage(sb.ToString); {AAAAAAAAAA}
sb.Free;
end;

//TStringBuilder.Append 试试其他数据类型
procedure TForm1.Button4Click(Sender: TObject);
var
sb: TStringBuilder;
b: Boolean;
r: Real;
begin
sb := TStringBuilder.Create;

b := True;
sb.Append(b);
sb.AppendLine;
b := not b;
sb.Append(b);
sb.AppendLine;

r := 100/3;
sb.Append(r);

ShowMessage(sb.ToString); {True
False
33.3333333333333}
sb.Free;
end;

//TStringBuilder.AppendFormat 的使用和 Format 函数是一样的
procedure TForm1.Button5Click(Sender: TObject);
var
sb: TStringBuilder;
begin
sb := TStringBuilder.Create;
sb.AppendFormat('%s %d', ['Delphi', 2009]);
ShowMessage(sb.ToString); {Delphi 2009}
sb.Free;
end;

end.