login.pas

这是delphi 的入门代码是我们为了一次考试而准备的

unit login;

interface

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

type
  Tloginfr = class(TForm)
    Edit1: TEdit;
    Edit2: TEdit;
    Button1: TButton;
    Button2: TButton;
    Label1: TLabel;
    Label2: TLabel;
    ADOConnection1: TADOConnection;
    ADODataSet1: TADODataSet;
    procedure Button1Click(Sender: TObject);
    procedure FormShow(Sender: TObject);
    procedure Button2Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  loginfr: Tloginfr;

implementation

{$R *.dfm}

procedure Tloginfr.Button1Click(Sender: TObject);
begin
     if edit1.Text='' then
     begin
       showmessage('请输入用户名!');
     end;
     self.ADODataSet1.Close;
     self.ADODataSet1.CommandText:='select * from loginta where userna ='+#39+trim(edit1.Text)+#39;
     self.ADODataSet1.Open;
     if self.ADODataSet1.IsEmpty then
     begin
       showmessage('用户名不存在!');
     end
     else
     begin
       if trim(edit2.Text)=self.ADODataSet1.FieldByName('passwd').AsString then
       begin
         showmessage('登录成功!');
       end
       else
       begin
         showmessage('密码不正确!');
       end;

     end;

end;

procedure Tloginfr.Button2Click(Sender: TObject);
begin
     //self.Close;
     Application.Terminate;
end;

procedure Tloginfr.FormShow(Sender: TObject);
begin
     edit1.Clear;
     edit2.Clear;
     edit2.PasswordChar:='*';
end;

end.