unitlogin.pas

Delphi与sqlserver应用。适用于初学者

unit UnitLogin;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls,UnitSystem, DB, ADODB, Provider, DBTables, DBClient, DBLocal, DBLocalB;
type
  TfrmLogin = class(TForm)
    Label1: TLabel;
    Label2: TLabel;
    edtUser: TEdit;
    edtPassword: TEdit;                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       
    btnOK: TButton;
    btnCancel: TButton;
    Label3: TLabel;
    procedure btnCancelClick(Sender: TObject);
    procedure btnOKClick(Sender: TObject);
    procedure UserLogin;
  private
    { Private declarations }
  public
    { Public declarations }

  end;
var
  frmLogin: TfrmLogin;
  tUsers:string;
  times:integer;
implementation
{$R *.dfm}
uses
    UnitData;
procedure TfrmLogin.btnCancelClick(Sender: TObject);
begin
    application.Terminate;
end;
procedure TfrmLogin.btnOKClick(Sender: TObject);
//var
   //Users,Passwords:string;
   //times:integer;
begin
   {times:=0;
   if times>2 then
   begin
   if Messagebox(handle,'你已尝试三次不成功了！请验证密码无误再试...'+#10+#13+'程序退出',
   '警告！',MB_OK+MB_ICONINFORMATION)=mrOK then     
   Application.Terminate;
   end  else 
   begin   }
   if  edtUser.Text<>'' then
     begin
        //inc(times);
        //Users:=ADOQlogin.FieldValues['users'];
        //Passwords:=ADOQlogin.FieldValues['passwords'];
        if  edtPassword.Text<>''  then
        begin //以后使用的变量
             tUsers:=trim(edtUser.Text);
             UserLogin;
        end else
        begin
            Application.MessageBox('密码验证失败，请输入正确的密码！','警告：',0+48);
            edtPassword.Text:='';
            edtPassword.SetFocus;
        end;
     end  else
     begin
       Application.MessageBox('请先输入用户名！','警告：',0+48);
       edtUser.SetFocus;
     end;
   //end;
end;
procedure TfrmLogin.UserLogin;
{var
   cnstr:string;
begin
   cnstr:='select * from TabLogin where users='''+edtUser.Text+''' and passwords='''+edtPassword.Text+'''';
   UnitData.DataModule1.ADOQ.Close();
   UnitData.DataModule1.ADOQ.SQl.Clear;
   UnitData.DataModule1.ADOQ.SQl.add(cnstr);
   UnitData.DataModule1.ADOQ.ExecSQL;
end;}
begin
   //inc(times);
try
   UnitData.DataModule1.ADOQ.Close;
   UnitData.DataModule1.ADOQ.SQL.Clear;
   UnitData.DataModule1.ADOQ.SQL.Text:='Select * From TabLogin where users='''+edtUser.Text+''' and passwords='''+edtPassword.Text+'''';
   UnitData.DataModule1.ADOQ.Open ;
   if UnitData.DataModule1.ADOQ.Bof and UnitData.DataModule1.ADOQ.Eof then
     begin
       Application.MessageBox('用户名或密码错误！'+#10#13+'请重新输入：','警告：',0+48);
       edtUser.SetFocus;
       edtUser.SelectAll;
     end
   else
     begin
       frmLogin.Hide;
       frmMain.ShowModal;
       frmLogin.FreeOnRelease;
     end;
except
    Application.MessageBox('数据库连接失败，请使用程序目录下MainServer.udl测试连接!', '提示', 0);
    ExitProcess(0);
end;
end;

end.