Access violation at address 0054619C in module 'MyQSObject.exe'. Read of address 00000000

写代码养猫 2008-09-25 01:44:18



procedure TFormHouse.btnSelectClick(Sender: TObject);

var

  sSQL:string;

begin

  sSQL := 'Select * From TB_House Where 1 > 0 ';

  if Trim(edt1.Text) <> '' then

    sSQL := sSQL + ' and HouseNum = ' + QuotedStr(edt1.Text) + '';

  if Trim(edt2.Text) <> '' then

    sSQL := sSQL + ' and HouseInfo = ' + QuotedStr(edt2.Text) + '';

  with Query do

  begin

    Connection := TDBConnector.Instance.Connection;  //执行到这出错 

    SQL.Text := sSQL;

    Open;

    ds1.DataSet := Query;

    dbgrdh1.DataSource := ds1;

  end;

end;

创建ADOConnection:



procedure TAccessConnector.StartConnect;

begin

  if not Assigned(Connection) then

    Connection := TADOConnection.Create(nil); 

  with Connection do

  begin

    LoginPrompt := False;

    ConnectionString := Format(ACCESSCONN_STR, [DBName, DBPassword]);  //DBName, DBPaddword读取配置文件

//ACCESSCONN_STR为常量:   ACCESSCONN_STR = 'Provider=Microsoft.Jet.OLEDB.4.0;Password="";'+

                          'Data Source=%s;Persist Security Info=True;'+

                          'Jet OLEDB:Database Password=%s';

    Open;

    FConnected := True;

  end;

end;

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