login.pas

四川大学图书管理系统！sql+c++实现

unit Login;

interface

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

type
  TLoginForm = class(TForm)
    Image1: TImage;
    GroupBox1: TGroupBox;
    Label1: TLabel;
    Label2: TLabel;
    Label3: TLabel;
    Edit1: TEdit;
    Edit2: TEdit;
    Button1: TButton;
    Button2: TButton;
    ComboBox1: TComboBox;
    procedure Button1Click(Sender: TObject);
    procedure Button2Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  LoginForm: TLoginForm;
  UseId,Types,Passwd:String;
  BackPasswd,BackTypes:String;

implementation

uses Data, Main;

{$R *.dfm}

procedure TLoginForm.Button1Click(Sender: TObject);
begin
  UseId := Edit1.Text;
  Passwd := Edit2.Text;
  Types := ComboBox1.Text;
  if UseId='' then  //登录证号为空
    begin
      Application.MessageBox('请输入登录证号','登录错误信息',MB_OK+MB_ICONEXCLAMATION);
    end
  else
    begin
      with Data.DataModule.LoginSelect do
      if Types='管理员' then
        begin
          Close;
          SQL.Clear;
          SQL.Add('select 工作编号,密码,管理员类型 from 管理员');
          SQL.Add('where 工作编号 = ''' + UseId + ''' and 密码 = ''' + Passwd +'''');
          Open;
          BackPasswd := FieldByName('密码').AsString;
          BackTypes := FieldByName('管理员类型').AsString;
          if BackTypes='' then //未在数据库中找到对应记录
            begin
              Application.MessageBox('无效的登录证号或密码！请确认无误后再输入','登录错误信息',MB_OK+MB_ICONEXCLAMATION);
            end
          else
            begin
              MainForm.Show;
              LoginForm.Hide;
            end
        end
      else if Types='借阅者' then
        begin
          Close;
          SQL.Clear;
          SQL.Add('select 读者证号,密码,读者类型 from 读者');
          SQL.Add('where 读者证号 = ''' + UseId + ''' and 密码 = ''' + Passwd +'''');
          Open;
          BackPasswd := FieldByName('密码').AsString;
          BackTypes := FieldByName('读者类型').AsString;
          if BackTypes='' then //未在数据库中找到对应记录
            begin
              Application.MessageBox('无效的登录证号或密码！请确认无误后再输入','登录错误信息',MB_OK+MB_ICONEXCLAMATION);
            end
          else
            begin
              BackTypes := '110';
              MainForm.Show;
              LoginForm.Hide;
            end
        end
    end;
    LoginForm.Edit1.Clear;
    LoginForm.Edit2.Clear;
end;

procedure TLoginForm.Button2Click(Sender: TObject);
begin
  LoginForm.Close;
end;

end.