delphi基础知识.ppt

1、2011.07,DELPHI基础知识,delphi历史,Delphi1：1995年 Delphi6：2001年 Delphi2007：CodeGear，2007年 Delphi XE2 Pulsar：embarcadero ，2011年 TIOBE：11-14,注释, Comment using curly braces (* Comment using paren and asterisk *) / double backslash comment,变量 常量,var i: Integer = 10; S: string = Hello world; D: Double = 3.141579

2、; const ADecimalNumber = 3.14;,操作符1,赋值 := Number1 := 5; 比较 =、=、 if x = y then DoSomething if x y then DoSomething 逻辑 not、and、or if (Condition 1) and (Condition 2) then DoSomething; while (Condition 1) or (Condition 2) do DoSomething; if not (condition) then (do something);,操作符2,算术 +、-、*、/、div、mod 位操

3、作 and、not、or、xor、shl、shr 自增自减过程 Inc（）、Dec（）,数据类型1,ShortInt： 8-bit 有符号整数 Byte：8-bit 无符号整数 SmallInt：16-bit 有符号整数 Word：16-bit 无符号整数 Integer、Longint： 32-bit 有符号整数 Cardinal、LongWord ： 32-bit无符号整数 Int64：64-bit 有符号整数 Single：4-byte 浮点数 Double：8-byte 浮点数,数据类型2,Extended：10-byte 浮点数 TDateTime：8-byte 日期，单位 天 Va

4、riant、OleVariant：变体类型 Char：1-byte 字符 WideChar：2-byte 字符 AnsiString：动态字符串 WideString ：动态宽字符串 Boolean：布尔型 PChar：NULL结尾字符串,动态内存分配,分配释放 AllocMem() FreeMem() GlobalAlloc() GlobalFree() GetMem() FreeMem() New() Dispose() StrAlloc() StrDispose() StrNew() StrDispose() VirtualAlloc() VirtualFree(),自定义类型1,数组

5、var A: array28.30 of Integer; A1: array1.2, 1.2 of Integer; i: Integer; begin for i := Low(A) to High(A) do Ai := i; end;,自定义类型2,动态数组 SA: array of string; SetLength(SA, 33); SA := nil;,自定义类型3,结构 Type MyRec = record i: Integer; d: Double; end; type TVariantRecord = record NullStrField: PChar; IntFiel

6、d: Integer; case Integer of 0: (D: Double); 1: (I: Integer); 2: (C: char); end;,自定义类型4,集合 type TCharSet = set of char; / possible members: #0 - #255 TEnum = (Monday, Tuesday, Wednesday, Thursday, Friday); TEnumSet = set of TEnum; / can contain any combination of TEnum members TSubrangeSet = set of 1

7、.10; / possible members: 1 - 10 TAlphaSet = set of A.z; / possible members: A - z AlphaSet := ; / Empty; no elements if S in CharSet then do something; Include(CharSet, a); / add a to set CharSet := CharSet + b; / add b to set Exclude(CharSet, x); / remove x from set CharSet := CharSet - y, z; / rem

8、ove y and z from set if a, b, c * CharSet = a, b, c then,自定义类型5,对象 Type TChildObject = class(TParentObject); SomeVar: Integer; procedure SomeProc; end;,自定义类型6,指针 Type PInt = Integer; PFoo = Foo; / PFoo is a pointer to a foo type Foo = record / A record type GobbledyGook: string; Snarf: Real; end; va

9、r P: Pointer; / Untyped pointer P2: PFoo; / Instance of PFoo,流程控制1,IF if x =100 then SomeFunction else if x = 200 then SomeOtherFunction else begin SomethingElse; Entirely; end;,流程控制2,CASE case SomeIntegerVariable of 101 : DoSomething; 202 : begin DoSomething; DoSomethingElse; end; 303 : DoAnotherTh

10、ing; else DoTheDefault; end;,流程控制3,FOR var I, X: Integer; begin X := 0; for I := 1 to 10 do inc(X, I); end.,流程控制4,WHILE var f: TextFile; / a text file s: string; begin AssignFile(f, foo.txt); Reset(f); while not EOF(f) do begin readln(f, S); writeln(S); end; CloseFile(f); end.,流程控制5,REPEAT var x: In

11、teger; begin X := 1; repeat inc(x); until x 100; end.,流程控制6,BREAK var i: Integer; begin for i := 1 to 1000000 do begin MessageBeep(0); / make the computer beep if i = 5 then Break; end; end;,流程控制7,CONTINUE var i: Integer; begin for i := 1 to 3 do begin writeln(i, . Before continue); if i = 1 then Co

12、ntinue; writeln(i, . After continue); end; end;,函数过程参数,传值 procedure Foo(s: string); 传引用 procedure ChangeMe(var x: longint); 不可变参数 procedure Goon(const s: string); 开放数组 function AddEmUp(A: array of Integer): Integer;,单元,Unit FooBar; interface uses BarFoo; public declarations here implementation uses

13、BarFly; private declarations here initialization unit initialization here finalization unit clean-up here end.,面向对象,封装Encapsulation 继承Inheritance 多态Polymorphism 字段 Field 方法Method 属性Property,类,TObject = class constructor Create; procedure Free; destructor Destroy; virtual; end; TFoo = class procedure

14、 IAmAStatic; procedure IAmAVirtual; virtual; procedure IAmADynamic; dynamic; end; var FooObject: TFoo; FooObject := TFoo.Create; FooObject.Free;,属性,TMyObject = class private SomeValue: Integer; procedure SetSomeValue(AValue: Integer); public property Value: Integer read SomeValue write SetSomeValue;

15、 end;,可见性,TSomeObject = class private/私有 APrivateVariable: Integer; AnotherPrivateVariable: Boolean; protected/单元内或子类 procedure AProtectedProcedure; function ProtectMe: Byte; public/公开 constructor APublicContructor; destructor APublicKiller; published/公开 运行时信息 property AProperty read APrivateVariabl

16、e write APrivateVariable; end;,接口1,type IUnknown = interface 00000000-0000-0000-C000-000000000046/GUID function QueryInterface(const IID: TGUID; out Obj): Integer; stdcall; function _AddRef: Integer; stdcall; function _Release: Integer; stdcall; end; IFoo = interface 2137BF60-AA33-11D0-A9BF-9A4537A42701 function F1: Integer; end; IBar = interface(IFoo) 2137BF61-AA33-11D0-A9BF-9A4537A42701 function F2: Integer; end;,接口2,type TFooBar = class(TInterfacedObject, IFoo, IBar) function F1: Integer; function F2: Integer; end; var FB: TFooBar; F: IFoo;