开发环境Delphi7
self报错问题
1 unit Unit1; 2 3 interface 4 5 uses 6 Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms, 7 Dialogs, StdCtrls,SysClass_u, ExtCtrls; 8 9 type 10 11 12 TForm1 = class(TForm) 13 Button1: TButton; 14 Button2: TButton; 15 Panel1: TPanel; 16 Button4: TButton; 17 procedure Button1Click(Sender: TObject); 18 procedure Button2Click(Sender: TObject); 19 procedure Button4Click(Sender: TObject); 20 21 private 22 { Private declarations } 23 public 24 { Public declarations } 25 end; 26 27 var 28 Form1: TForm1; 29 30 procedure sssss(aObj,Sender: Tobject); 31 32 implementation 33 34 uses 35 Unit3; 36 37 {$R *.dfm} 38 procedure sssss(aObj,Sender: Tobject); 39 begin 40 ShowMessage(TForm(aObj).name); //如果Button4点击过 ，再点击Button2,这句也会报错 //和Button1Click中注释的那句一样 41 ShowMessage(TForm(Sender).name); 42 ShowMessage('000'); 43 end; 44 procedure TForm1.Button1Click(Sender: TObject); 45 var 46 s:Integer; 47 begin 48 //为了证明Self赋值问题，self其实是一个隐形参数 49 //ShowMessage(self.name);会报错 50 ShowMessage(IntToStr(Integer(@self))); //这个比下面的这个Integer(@Sender)大四个字节 51 ShowMessage(IntToStr(Integer(@Sender)));//这个比下面的这个Integer(@s)大四个字节 52 ShowMessage(IntToStr(Integer(@s))); 53 //由这几个地址充分证明了self是一个隐形参数 54 //学过汇编应该清楚栈相关的问题，栈的内存大小是定死的，是由程序编译时就定义好了，集成开发环境都有对栈的大小进行设置； 55 //栈是由高地址向低地址延伸的，比如当前栈顶地址为200208，压一个32位的Integer进去后，当前栈顶为200204 56 //不做过多解释 57 //仅做个笔记 58 59 ShowMessage((Sender as TComponent ).name); 60 end; 61 62 procedure TForm1.Button2Click(Sender: TObject); 63 var 64 s:TNotifyEvent; 65 begin 66 s:=Button1.onClick; 67 sss(@s); 68 end; 69 70 procedure TForm1.Button4Click(Sender: TObject); 71 var 72 s:TNotifyEvent; 73 begin 74 @Button1.onClick:=@sssss;//把sssss赋值给Button1.onClick 75 end; 76 77 end.
1 unit Unit3; 2 3 interface 4 5 uses 6 Classes,Forms; 7 procedure sss(pp:Pointer); 8 9 implementation 10 11 uses 12 Unit2; 13 14 procedure sss(pp:Pointer); 15 begin 16 Form2:=TForm2.Create(Application); 17 @Form2.OnMyProc:=pp; 18 Form2.Show; 19 end; 20 end.
1 unit Unit2; 2 3 interface 4 5 uses 6 Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms, 7 Dialogs, StdCtrls,SysClass_u; 8 9 type 10 TForm2 = class(TForm) 11 Button1: TButton; 12 procedure FormDestroy(Sender: TObject); 13 procedure Button1Click(Sender: TObject); 14 private 15 FOnMyProc:TNotifyEvent; 16 { Private declarations } 17 public 18 property OnMyProc :TNotifyEvent read FOnMyProc write FOnMyProc; 19 { Public declarations } 20 end; 21 22 var 23 Form2: TForm2; 24 implementation 25 26 {$R *.dfm} 27 28 procedure TForm2.FormDestroy(Sender: TObject); 29 begin 30 OnMyProc:=nil; 31 end; 32 33 procedure TForm2.Button1Click(Sender: TObject); 34 begin 35 OnMyProc(Sender ); 36 end; 37 38 end.
