在Windows下使用QCreator时，当编写如下代码时有错误：
#ifndef LOGINDLG_H
#define LOGINDLG_H
#include <QtGui/QtGui>
class QLineEdit;
class CLoginDlg : Public QDialog
{
Q_OBJECT
public:
CLoginDlg(QWidget* =0);
public slots:
virtual void accept();
private:
QLineEdit* usrLineEdit;
QLineEdit* pwdLineEdit;
};
#endif
错误：
error: expected class-name before "QDialog"
error: aggregate `CLoginDlg dlg' has incomplete type and cannot be defined
哪位Qt高手指点一下，不胜感激！
