高手,帮忙看下是那里出错了

Question

我用ADOConnection控件来连接SQL数据库,编译通过了,可是在用登陆窗口登陆时出现这个错误 "project   database.exe   raise   exception   class   EAccessViolation   with   message   'Accessviolation   at   address   00486EA1   in   module   database.exe'.Read   of   address   000002FC'.Process   stopped"。想问下这个是怎么回事？代码如下：
unit userver;interfaceuses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs,ExtCtrls,ShellAPI, Menus, DB, DBTables,INIFiles, ADODB;
const
  CM_RESTORE=WM_USER+$1000;
  WZGL_APP_NAME='WZGL_System';
  WM_WZGLNOTIFY=WM_USER+100;
  strNotifyTip='物资管理应用服务器';
  ID_MAIN=100;
type
  TfrmMain = class(TForm)
    PopupMenu: TPopupMenu;
    NshowForm: TMenuItem;
    NClose: TMenuItem;
    ADOConnection: TADOConnection;
    procedure NCloseClick(Sender: TObject);
    procedure FormDestroy(sender:Tobject);
    procedure NshowFormClick(Sender: TObject);
    procedure Formcreate(Sender: TObject);  private
    { Private declarations }
  public
  procedure Createparams(var params:TCreateparams);override;
  procedure Restorerequest(var message:TMessage);message CM_RESTORE;
  procedure Notify(var Msg:TMessage);message WM_WZGLNOTIFY;
  procedure minimize(sender:Tobject);
  function DBConnect(aServerName,aDatabaseName,aUserName,aPassword:string):boolean;
    { Public declarations }
  end;var
  frmMain: TfrmMain;
  nid:NotifyIconData;implementation
uses
  BDConnectFrm;
  procedure TfrmMain.Createparams(var params:TCreateparams);
  begin
  inherited createparams(Params);
  params.winclassname:=WZGL_APP_NAME;
  end;
  procedure TfrmMain.restorerequest(var message:TMessage);
  begin
  if isiconic(Application.Handle)=true then
     application.restore
  else
     application.bringtofront;
  end;  {$R *.dfm}procedure TfrmMain.NCloseClick(Sender: TObject);
begin
    close;
end;
procedure TfrmMain.Notify(var Msg:TMessage);
  var
  pt:TPoint;
  begin
     case msg.LParam of
        WM_RBUTTONDOWN:
        begin
             SetForeGroundWindow(nid.Wnd);
             GetCursorPos(pt);
             Popupmenu.Popup(pt.X,pt.Y);
        end;
        WM_LBUTTONDOWN:
        begin
          application.Minimize;
          frmMain.Hide;
        end;
        WM_LBUTTONDBLCLK:
        begin
           showwindow(application.Handle,SW_SHOWNORMAL);
        end;
  end;
end;
procedure TfrmMain.minimize(sender:Tobject);
begin
     nid.cbSize:=sizeof(NOTIFYICONDATA);
     nid.Wnd:=handle;
     nid.uID:=ID_MAIN;
     nid.hIcon:=Application.Icon.Handle;
     strcopy(nid.szTip,strnotifytip);
     nid.uFlags:=NIF_MESSAGE or NIF_ICON or NIF_TIP;
     nid.uCallbackMessage:=WM_WZGLNOTIFY;
     Shell_NotifyIcon(NIM_ADD,@nid);
     showwindow(application.Handle,SW_HIDE);
end;
Procedure TfrmMain.Formcreate(sender:Tobject);
var
  serverName,databaseName,userName,password:string;
  begin
    ReadFormIni(serverName,databaseName,userName,password);
    if not DBConnect(ServerName,DatabaseName,UserName,Password) then
       if not DBConnectExecute(TfrmDBConnect) then
          application.Terminate;
    application.OnMinimize:=minimize;
  end;
procedure TfrmMain.FormDestroy(sender:Tobject);
  begin
     nid.cbSize:=sizeof(NOTIFYICONDATA);
     nid.Wnd:=Handle;
     nid.uID:=ID_MAIN;
     nid.uFlags:=0;
     Shell_NotifyIcon(NIM_DELETE,@nid);
  end;
procedure TfrmMain.NshowFormClick(Sender: TObject);
begin
  showwindow(application.Handle,SW_SHOWNORMAL);
end;
function TfrmMain.DBConnect(aServerName,aDatabaseName,aUserName,aPassword:string):boolean;
begin
result:=true;
ADOConnection.Connected:=false;
ADOConnection.ConnectionString:='Provider=SQLOLEDB.1'+';Persist Security Info=true'+';User ID='+aUserName+';password='+aPassword+';Initial Catalog='+aDatabaseName+';Data Source='+aServerName;
try
  ADOConnection.Connected:=true;
except
  result:=false;
end;
end;
end.
unit BDConnectFrm;interfaceuses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls,INIFiles;type
  TfrmDBConnect = class(TForm)
    Label1: TLabel;
    Label2: TLabel;
    Label3: TLabel;
    Label4: TLabel;
    Button1: TButton;
    Button2: TButton;
    EdtServerName: TEdit;
    edtDatabaseName: TEdit;
    EdtUserName: TEdit;
    EdtPassword: TEdit;
    procedure Button1Click(Sender: TObject);
    procedure Button2Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;
procedure ReadFormini(var aServerName,aDatabaseName,aUserName,aPassword:string);
procedure WriteToini(const aServerName,aDatabaseName,aUserName,aPassword:string);
function DBConnectExecute(aClass:TFormClass):boolean;
var
  frmDBConnect: TfrmDBConnect;
  connected:boolean;implementation
uses
  userver;{$R *.dfm}function DBConnectExecute(aClass:TFormClass):boolean;
begin
   try
      frmMain.ShowModal;
   finally
      frmMain.free;
      result:=connected;
   end;
end;
procedure ReadFormini(var aServerName,aDatabaseName,aUserName,aPassword:string);
var
  IniFile:TIniFile;
  FileName:string;
begin
  FileName:=ExtractFilePath(application.ExeName)+'\DB.ini';
  IniFile:=TInifile.Create(FileName);
  aServerName:=IniFile.ReadString('DB','ServerName','');
  aDatabaseName:=IniFile.ReadString('DB','DatabaseName','');
  aUserName:=Inifile.ReadString('DB','UserName','');
  aPassword:=Inifile.ReadString('DB','Password','');
  Inifile.Free;
end;
procedure WriteToini(const aServerName,aDatabaseName,aUserName,aPassword:string);
var
  IniFile:TIniFile;
  FileName:string;
begin
  FileName:=ExtractFilePath(application.ExeName)+'\DB.ini';
  IniFile:=TInifile.Create(FileName);
  IniFile.WriteString('DB','ServerName',aServerName);
  IniFile.WriteString('DB','DatabaseName',aDatabaseName);
  IniFile.WriteString('DB','UserName',aUserName);
  IniFile.WriteString('DB','Password',aPassword);
  IniFile.Free;
end;
procedure TfrmDBConnect.Button1Click(Sender: TObject);
begin
  WriteToini(edtServerName.Text,edtDatabaseName.Text,edtUserName.Text,edtPassword.Text);
  if frmMain.dbconnect(edtServerName.Text,edtDatabaseName.Text,edtUserName.Text,edtPassword.Text) then
    begin
       application.MessageBox('数据库连接成功','提示',Mb_IconInformation+Mb_Okcancel);
       Connected:=true;
       close;
    end
  else
    begin
       application.MessageBox('数据库连接失败，请确认后再输入','提示',Mb_Iconwarning+mb_ok);
    end;
end;procedure TfrmDBConnect.Button2Click(Sender: TObject);
begin
   close;
end;end.

Answer 1

这样试试，把你的Form的OnCreate的事件，放到OnActivate事件中试试>>Procedure TfrmMain.Formcreate(sender:Tobject);//create中的事件，转到
var
serverName,databaseName,userName,password:string;
begin
ReadFormIni(serverName,databaseName,userName,password);
if not DBConnect(ServerName,DatabaseName,UserName,Password) then
if not DBConnectExecute(TfrmDBConnect) then
application.Terminate;
application.OnMinimize:=minimize;
>>>end;
======================================
Procedure TfrmMain.FormActivate(sender:Tobject);
var
serverName,databaseName,userName,password:string;
begin
ReadFormIni(serverName,databaseName,userName,password);
if not DBConnect(ServerName,DatabaseName,UserName,Password) then
if not DBConnectExecute(TfrmDBConnect) then
application.Terminate;
application.OnMinimize:=minimize;
end;

Answer 2

在formclose中将adoconnection关闭试试。

Answer 3

还是不行啊,它停在了这句'ADOConnection.Connected:=false;'不动了,现在不知道是那出了问题了