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unit psd;
interface
uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, StdCtrls, DB, DBTables;
type
TForm1 = class(TForm)
Table1: TTable;
Label1: TLabel;
Label2: TLabel;
Label3: TLabel;
Edit1: TEdit;
Edit2: TEdit;
Button1: TButton;
Button2: TButton;
procedure Button1Click(Sender: TObject);
procedure Button2Click(Sender: TObject);
procedure FormCreate(Sender: TObject);
procedure Edit2Change(Sender: TObject);
private
{ Private declarations }
public
{ Public declarations }
end;
var
Form1: TForm1;
count:integer; //设置全程整型变量作为计数器
implementation
{$R *.dfm}
procedure TForm1.Button1Click(Sender: TObject);
var
results:variant;
begin
if Edit1.Text='' then
showmessage('用户名不能为空!');
if Edit2.Text='' then
showmessage('请输入密码!');
count:=count+1;//计数加1
results:=table1.Lookup('users',Edit1.Text,'password');
//检索数据库中对应的用户名的密码项
if results=Edit2.Text then
showmessage('密码确认,即将进入学生信息管理系统。')
//如果对应相同则进入,此处只是演示,所以只是简单说明密码确认
else
begin
showmessage('错误的用户名或密码!');//密码不确认
if(count=3) then
close;//三次错误,强制退出
end;
end;
procedure TForm1.Button2Click(Sender: TObject);
begin
Application.Terminate;
end;
procedure TForm1.FormCreate(Sender: TObject);
begin
table1.Active:=true;//窗体初始化,连接数据库
count:=0
end;
procedure TForm1.Edit2Change(Sender: TObject);
begin
if(Edit2.Text=#13) then//当在edit2中输入密码后,按回车键,执行密码查询
Button1.Click
else
end;
end. |
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