APP
as是把某个类型对象转换成所需要的类型。
is是判断某对象是否是某类型。
unit Unit1;
interface
uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, StdCtrls;
type
TForm1 = class(TForm)
Edit1: TEdit;
Edit2: TEdit;
Edit3: TEdit;
Button1: TButton;
procedure Button1Click(Sender: TObject);
private
{ Private declarations }
public
{ Public declarations }
end;
var
Form1: TForm1;
implementation
{$R *.dfm}
procedure TForm1.Button1Click(Sender: TObject);
var i:Integer;
begin
for i:= 0 to ControlCount - 1 do
begin
if Controls[i] is TEdit then
if (Controls[i] as TEdit).Text <> '' then
begin
(Controls[i] as TEdit).Text := 'haha';
end;
end;
end;
end.
窗体控件
Tedit 1、Tedit 2、Tedit 3、Tbutton
本文摘自 ：https://www.cnblogs.com/
