unit Login_Unit;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, XPMan, jpeg, ExtCtrls, StdCtrls, Mask, DBCtrls, Buttons, DB,
  ADODB;

type
  TLogin_Form = class(TForm)
    BitBtn2: TBitBtn;
    BitBtn1: TBitBtn;
    Label4: TLabel;
    Image1: TImage;
    Panel1: TPanel;
    Label3: TLabel;
    Label2: TLabel;
    ComboBox1: TComboBox;
    Edit1: TEdit;
    ADOConnection1: TADOConnection;
    ADOQuery1: TADOQuery;
    procedure BitBtn2Click(Sender: TObject);
    procedure FormCreate(Sender: TObject);
    procedure BitBtn1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Login_Form: TLogin_Form;
  username:String;
  
implementation
   uses Main_Unit;
{$R *.dfm}

procedure TLogin_Form.BitBtn2Click(Sender: TObject);
begin
    if l then
       Application.Terminate
    else
       Login_Form.Hide;
end;

procedure TLogin_Form.FormCreate(Sender: TObject);
var
  con:Tstringlist;
  i,count:Integer;
  temp_username:array[1..30] of String;
begin
 con := TStringlist.Create;
 l:=true;
try
 try
   con.LoadFromFile(ExtractFilePath(Application.ExeName)+'config.txt');
   Self.ADOConnection1.Close;
   Self.ADOConnection1.ConnectionString := 'Provider=Microsoft.Jet.OLEDB.4.0;Data Source='+con.Strings[0]+'Persist Security Info=False';
   Self.ADOConnection1.LoginPrompt := False;
   Self.ADOConnection1.Connected := True;
   Self.ComboBox1.Text:=Self.ComboBox1.Items[0]; //顯示第一條記錄*)
 except
   begin
      MessageDlg('系統初始化失敗，請與開發人員聯系!',mtWarning,[mbOk],0);
      Application.Terminate;
   end;
 end;
 finally
  con.Free;
 end;
   with Self.ADOQuery1 do          //添加用戶
     begin
         Self.ADOQuery1.Close;
         Self.ADOQuery1.SQL.Clear;
         Self.ADOQuery1.SQL.Add('select * from Login_Table');
         Self.ADOQuery1.Open;
         Self.ADOQuery1.First;
         count:=Self.ADOQuery1.RecordCount;

         //將所有用戶名放入數組temp_username中
         for i:=1 to count do
            begin
               temp_username[i]:=FieldByName('用戶名').AsString;
               Self.ADOQuery1.Next;
            end;
         //將所有用戶添加到列表框中
         for i:=1 to count do
            begin
               Self.ComboBox1.Items.Add(temp_username[i]);
            end;
     end;
  Self.ComboBox1.Text:=Self.ComboBox1.Items[0]; //將第一個用戶名添回到列表框中
end;

procedure TLogin_Form.BitBtn1Click(Sender: TObject);
var
  pass:String;
begin
    username:=Self.ComboBox1.Text;
    with Self.ADOQuery1 do
        begin
           Self.ADOQuery1.Close;
           Self.ADOQuery1.SQL.Clear;
           Self.ADOQuery1.SQL.Text:='select * from Login_Table where 用戶名=:p';
           Self.ADOQuery1.Parameters.ParamByName('p').Value:=username;
           Self.ADOQuery1.Open;
           pass:=FieldByName('密碼').AsString;  //取出密碼
        end;
    if Self.Edit1.Text=pass then
       Main_Form.Show
    else
       begin
          MessageDlg('密碼錯誤，請重新輸入！',mtError,[mbOk],0);
          Self.Edit1.Clear;
          Self.Edit1.SetFocus;
          Exit;
       end;
  
end;

end.