其它 Helper

TByteHelper

TShortIntHelper

TSmallIntHelper

TWordHelper

TCardinalHelper

TIntegerHelper

TInt64Helper

TUInt64Helper

TNativeIntHelper

TNativeUIntHelper

---

// 它们定义在 System.SysUtils, 功能基本一样, 常用的有:

var

  I: Integer;

  S: string;

begin

  I := I.MaxValue;     //  2147483647

  I := I.MinValue;     // -2147483648

  I := I.Size;         // 4

  I := I.Parse('123'); // 123



  I := 255;

  S := I.ToString();     // '255'

  S := I.ToHexString;    // FF

  S := I.ToHexString(4); // 00FF

end;

---

TBooleanHelper

TByteBoolHelper

TWordBoolHelper

TLongBoolHelper

---

// 它们定义在 System.SysUtils, 基本无用.

---

TSingleHelper

TDoubleHelper

TExtendedHelper

---

// 它们定义在 System.SysUtils, 功能基本一样, 常用的有:

var

  F: Double;

  S: string;

begin

  F := F.MaxValue;      // 1.7976931348623157081e+308

  F := F.MinValue;      // -1.7976931348623157081e+308

  F := F.Size;          // 8

  F := F.Parse('3.14'); // 3.14



  F := Pi * 100;

  s := F.ToString();                      // 314.159265358979

  S := F.ToString(ffExponent, 6, 3);      // 3.14159E+002

  S := F.ToString(ffFixed, MaxInt, 2);    // 314.16; 保留两位小数点; 同 S := Format('%.2f', [F]);

  S := F.ToString(ffCurrency, MaxInt, 4); // ¥314.1593

end;

---

TCharHelper

---

// 它们定义在 System.Character, 它可以彻底替代同单元的 TCharacter 结构体. 主要方法有:

function IsControl: Boolean;

function IsDigit: Boolean;

function IsHighSurrogate: Boolean;

function IsInArray(const SomeChars: array of Char): Boolean;

function IsLetter: Boolean;

function IsLetterOrDigit: Boolean;

function IsLower: Boolean;

function IsLowSurrogate: Boolean;

function IsNumber: Boolean;

function IsPunctuation: Boolean;

function IsSeparator: Boolean;

function IsSurrogate: Boolean;

function IsSymbol: Boolean;

function IsUpper: Boolean;

function IsWhiteSpace: Boolean;

function ToLower: Char;

function ToUpper: Char;

function ToUCS4Char: UCS4Char;



// 以后可以不用 CharInSet()了, 不过得引用 System.Character 单元



uses System.Character;



procedure TForm1.FormCreate(Sender: TObject);

begin

  KeyPreview := True;

end;



procedure TForm1.FormKeyPress(Sender: TObject; var Key: Char);

begin

  if Key.IsInArray(['1', '2', '3', '4', '5', '6', '7', '9', '0']) then

    ShowMessage('按下了数字键');



  if Key.IsNumber then

    ShowMessage('真的按下了数字键');

end;

---

System.SysUtils 还给了一个 TGuidHelper

---

var

  G: TGUID;

  S: string;

  bs: TBytes;

begin

  G := G.NewGuid;

  S := G.ToString;

  bs := G.ToByteArray;

end;



// XE4 中还看到几个 Helper, 如:

TCriticalSectionHelper

TConditionVariableHelper

CFGregorianDateHelper

TD2DMatrix3x2FHelper

TDSSessionHelper

TCanvasHelper

TStyleManagerHelper

TBitmapHelper

TContextHelper

TElementMarginsHelper

TThemeServicesClassHelper



// 这都不常用了, 不过这东西确实方便批量地扩展功能, 这或许会成为写代码的一种基本手法, 譬如:

// System.Rtti 单元中的 TListHelper, TArrayHelper 和 System.Classes 单元中的 TUInt32Helper

---