login.pas

用Delphi做的一个学生数据库系统

unit login;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls, Buttons, ExtCtrls;

type
  TloginForm = class(TForm)
    Panel1: TPanel;
    btn_ok: TBitBtn;
    btn_cancel: TBitBtn;
    Panel2: TPanel;
    Label1: TLabel;
    image: TImage;
    Label2: TLabel;
    Edit1: TEdit;
    Edit2: TEdit;
    procedure btn_okClick(Sender: TObject);
    procedure btn_cancelClick(Sender: TObject);
    procedure Edit1Change(Sender: TObject);
    procedure Edit2KeyPress(Sender: TObject; var Key: Char);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  loginForm: TloginForm;

implementation

uses dm;

{$R *.dfm}

procedure TloginForm.btn_okClick(Sender: TObject);
  var
 sql:string;
begin
  sql:='select * from login where username=:a and passwrd=:b';

  dmform.ADOQuery_login.Close;
  dmform.ADOQuery_login.SQL.Clear;
  dmform.ADOQuery_login.SQL.Add(sql);

  dmform.ADOQuery_login.Parameters[0].Value:=edit1.Text;
  dmform.ADOQuery_login.Parameters[1].Value:=edit2.Text;
  dmform.ADOQuery_login.Open;

  if dmform.ADOQuery_login.RecordCount>0 then
  begin
    loginform.ModalResult:=mrok;
  end
  else
  begin
    application.MessageBox('用户名或者密码错误,请重新输入!','登录提示',mb_ok);
    edit1.Text:='';
    edit2.Text:='';
    edit1.SetFocus;
  end;
end;

procedure TloginForm.btn_cancelClick(Sender: TObject);
begin
loginform.ModalResult:=mrCancel;
end;

procedure TloginForm.Edit1Change(Sender: TObject);
begin
 if (Trim(edit1.Text)<>'')or(Trim(edit2.Text)<>'')then
   btn_ok.Enabled:=true
   else
    btn_ok.Enabled:=false;
 end;

procedure TloginForm.Edit2KeyPress(Sender: TObject; var Key: Char);
begin
 if key=#13 then
 begin
    btn_okClick(Sender);
 end;

end;

end.