login.pas

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unit Login;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls, DB, ADODB, DBTables;

type
  TLoginFrm = class(TForm)
    Label1: TLabel;
    Label2: TLabel;
    Label3: TLabel;
    Edit1: TEdit;
    Button1: TButton;
    Button2: TButton;
    ADOQuery1: TADOQuery;
    Edit2: TEdit;
    ADOConnection1: TADOConnection;
    procedure Button1Click(Sender: TObject);
    procedure Button2Click(Sender: TObject);
    
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  LoginFrm: TLoginFrm;

implementation

uses Main;

{$R *.dfm}

procedure TLoginFrm.Button1Click(Sender: TObject);
var username,password:string; 
begin
    
   if edit1.Text='' then
      messagebox(LoginFrm.handle,'请输入用户名','警告',mb_ok+mb_iconwarning)
   else
      if edit1.Text='' then
         messagebox(LoginFrm.handle,'请输入密码','警告',mb_ok+mb_iconwarning)
   else
    begin
    username:=edit1.text;
    password:=edit2.text;
     with ADOQuery1 do
      begin
       close;
       sql.clear;
       sql.add('select * from login where username=');
       sql.add(''''+username+''''+'and password='+''''+password+'''');
       open;
       first;
       if recordcount=1 then
          begin
           LoginFrm.Hide;
           MainFrm.Show;
          end
      else
         messagebox(LoginFrm.handle,'请输入正确的密码','警告',mb_ok+mb_iconwarning);
      end;
    end;
end;

procedure TLoginFrm.Button2Click(Sender: TObject);
begin
   Application.terminate;
end;



end.