很急，很急的问题

Question

我以前没有用过deophi，向解决如下的问题
有一个数据库equip里面有一张表user;
现在做一个登陆的程序，登陆时连接数据库，登陆名称和登陆密码输入与数据库user表的数据相比较，对了就进入查询，不对就抱错，请问登陆时怎么做？
给出源码，
很急，很急，马上就要用，解决了给100分

Answer 1

unit Unit1;interfaceuses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, DB, ADODB, StdCtrls;type
  TForm1 = class(TForm)
    Edit1: TEdit;
    Label1: TLabel;
    Label2: TLabel;
    Edit2: TEdit;
    Button1: TButton;
    Button2: TButton;
    ADOTable1: TADOTable;
    procedure Button1Click(Sender: TObject);
    procedure Button2Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;var
  Form1: TForm1;implementationuses Unit2;{$R *.dfm}
procedure TForm1.Button1Click(Sender: TObject);
begin
        if not adotable1.Locate('name',edit1.Text,[]) then
          showmessage('不存在这个用户,登陆失败')
          else
            if adotable1.FieldValues['password']=edit2.Text then
            begin
            form2.Show;
            form1.Hide;
            end
            else
             begin
              showmessage('密码错误,请从新登陆');
              application.Terminate;
            end;end;procedure TForm1.Button2Click(Sender: TObject);
begin
form1.close;
end;end.

Answer 2

我也来一个
unit Unit5;interfaceuses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls, DB, DBTables;type
  TForm5 = class(TForm)
    Button1: TButton;
    GroupBox1: TGroupBox;
    Button2: TButton;
    Edit1: TEdit;
    Edit2: TEdit;
    Label1: TLabel;
    Label2: TLabel;
    Label3: TLabel;
    Table1: TTable;
    procedure Button1Click(Sender: TObject);
    procedure FormKeyPress(Sender: TObject; var Key: Char);
    procedure Button2Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;var
  Form5: TForm5;
  sUserID,sUserPW: string;implementationuses Unit1;{$R *.dfm}procedure TForm5.Button1Click(Sender: TObject);
begin
try
table1.Filter:='name='''+edit1.text+'''';
table1.Filtered:=true;
table1.Open;
Except
Application.MessageBox('数据库连接失败，请于系统管理员联系。','数据库连接错误！',MB_OK);
Application.Terminate;
end;
if table1.recordcount=1 then
  begin
   if table1['password']=edit2.text then
    begin
     sUserID := Trim(edit1.Text);
     sUserPW := Trim(edit2.Text);
     self.ModalResult:=mrOK;
     end
    else
      begin
      Application.MessageBox('密码输入有误，请确认密码!','密码不正确!',MB_OK);
      edit2.SetFocus;
      end;
  end
else  Application.MessageBox('请确认用户名是否正确!','无此用户!',MB_OK);  edit1.SetFocus;
end;procedure TForm5.FormKeyPress(Sender: TObject; var Key: Char);
begin
if Key = #13 then { 如 果 按 下 了 回 车 键 }
begin
Key := #0; { 吃 掉 回 车 键 }
Perform(WM_NEXTDLGCTL,0,0); { 移 动 到 下 一 个 控 制 }
end;
end;procedure TForm5.Button2Click(Sender: TObject);
begin
close;
end;end.

Answer 3

//  edit1.text为用户名输入框;
  //  edit2.text为密码输入框  
    user.Filter:='id='''+edit1.Text+'''';
    user.Filtered:=true;
    user.Open;
  if user.RecordCount=1 then     //判断登陆名
   begin
     if user['passwd']=edit2.Text then
       begin
       ....查询
       end
     else showmessage('密码不对！');
   end
  else showmessage('无此用户!')

Answer 4

我这样做怎么发生错误
procedure Tlogin.LoginBtnClick(Sender: TObject);
begin
username:=login.Edit1.Text;
paswd:=login.Edit2.Text;
 pathst:=getcurrentdir()+'\mdb\equip.mdb;';
  st:='Provider=Microsoft.Jet.OLEDB.4.0;Data Source=E:\EquipManage\mdb\equip.mdb;Persist Security Info=False';
  ADOConnection1.ConnectionString:=st;
  ADOConnection1.Connected:=true;
  if not ADOTable1.Locate('username',username,[])then
  begin
       FLogError.ShowModal;
       ADOTable1.Close;
       ADOConnection1.Close;
       end
  else if ADOTable1.FieldValues['pswd']=paswd then
            begin
                FsearchG1.ShowModal;
                login.Hide;
                ADOTable1.Close;
                ADOConnection1.Close;
                end
        else begin
           FLogError.ShowModal;
           ADOTable1.Close;
           ADOConnection1.Close;
           end;
end;end.
说是什么对想打开是操作不被允许

Answer 5

ADOConnection1.Connected:=true;
>>  adotable1.Connection:=ADOConnection1;
>>  adotable1.TableName:=user;
  if not ADOTable1.Locate('username',username,[])then

Answer 6

procedure TFrmLogin.BtnLoginClick(Sender: TObject);
begin
   DataModule1.UserTable.Active:=true;
   if EdtUser.Text='' then
   begin
      ShowMessage('请输入用户名!');
      EdtUser.SetFocus;
      exit;
   end;
   if DataModule1.UserTable.Locate('username;userpwd',VarArrayOf([EdtUser.Text,EdtPassword.Text]),
      []) then
        begin
          UName:=EdtUser.Text;
          Upwd:=EdtPassword.Text;
          FormMain.Show;
          FrmLogin.Hide;
        end
   else
      begin
        ShowMessage('请输入正确的密码');
        EdtPassword.SetFocus;
        exit;
      end;
  end;

Answer 7

楼主在做如下操作时：
ADOConnection1.ConnectionString:=st;
ADOConnection1.Connected:=true;
必须保证在设计的时候ADOConnection1的Connected为False；否则就会出现上面所说的“对想打开是操作不被允许
”