Delphi经典实例3------句柄演示

如下图所示建立工程：

代码如下：

unit mainunit;interfaceuses Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms, Dialogs, StdCtrls;type TForm1 = class(TForm) Button1: TButton; Button2: TButton; Edit1: TEdit; Label1: TLabel; Button3: TButton; Button4: TButton; procedure Button1Click(Sender: TObject); procedure FormShow(Sender: TObject); procedure Button2Click(Sender: TObject); procedure Button3Click(Sender: TObject); procedure Button4Click(Sender: TObject); private { Private declarations } public { Public declarations } end;var Form1: TForm1;implementation{$R *.dfm}procedure TForm1.Button1Click(Sender: TObject);begin Showmessage('主窗体的句柄是：'+IntToStr(Form1.Handle));end;procedure TForm1.FormShow(Sender: TObject);begin Button1.SetFocus;end;procedure TForm1.Button2Click(Sender: TObject);begin Showmessage('当前鼠标点击的按钮的句柄是：'+IntToStr(Button2.Handle));end;procedure TForm1.Button3Click(Sender: TObject);begin if (Application.MessageBox('是否决定改变主窗体的标题','询问',MB_OKCANCEL + MB_OK)=ID_OK) then begin SetWindowText(Form1.Handle, Pchar(Edit1.Text)); if (Edit1.Text='')then ShowMessage('用户将主窗体的标题设置为空!') else ShowMessage('用户将主窗体的新标题设置为：'+Edit1.Text); Button3.SetFocus; end else begin ShowMessage('用户取消了修改主窗体标题的操作!'); Button3.SetFocus; end;end;procedure TForm1.Button4Click(Sender: TObject);begin Close;end;end.