C++ GUI Programming with Qt 4 SortDialog作成時にエラーが発生します。

C++ GUI Programming with Qt 4　gotocelldialog-作成時にエラーが発生します

と似た質問なのですが、ご勘弁ください。この質問でご回答いただいたように、
したつもりなのですが、今度は、

認識できない型　Ui::SortDialogが使われています。
Ui::SortDialogの宣言を確認してください。

というエラーが出ます。以前の回答の通りに倣って見たのですが、
スムーズにはいきませんでした。

色々とコードをいじってみて実行してみましたが、
糸が絡まるばかり。以下のコードはできるだけもとに戻して
いるつもりですが、どこをどうすればエラーが解決するのでしょうか。
特に、
sortdialog.cpp内のui->に下線が。
delete に下線が引かれます。
他は事前のエラーの兆候は見受けられません。

Windows-10 Qt5.9.6 Qt-Creator4.7.0

sort.pro

    #-------------------------------------------------
    #
    # Project created by QtCreator 2018-09-08T16:20:41
    #
    #-------------------------------------------------

    QT       += core gui widgets

    TARGET = sort
    TEMPLATE = app

    # The following define makes your compiler emit warnings if you use
    # any feature of Qt which has been marked as deprecated (the exact warnings
    # depend on your compiler). Please consult the documentation of the
    # deprecated API in order to know how to port your code away from it.
    DEFINES += QT_DEPRECATED_WARNINGS

    # You can also make your code fail to compile if you use deprecated APIs.
    # In order to do so, uncomment the following line.
    # You can also select to disable deprecated APIs only up to a certain version of Qt.
    #DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0x060000    # disables all the APIs deprecated before Qt 6.0.0

    CONFIG += c++11\
            uitools

    SOURCES += \
               main.cpp \
            sortdialog.cpp

    HEADERS += \
            sortdialog.h

    FORMS += \
            sortdialog.ui

    # Default rules for deployment.
    qnx: target.path = /tmp/$${TARGET}/bin
    else: unix:!android: target.path = /opt/$${TARGET}/bin
    !isEmpty(target.path): INSTALLS += target

sortdialog.h

#ifndef SORTDIALOG_H
#define SORTDIALOG_H
#include <QDialog>
#include "ui_sortdialog.h"
namespace Ui {
class SortDialog;
}
class SortDialog : public QDialog
{
    Q_OBJECT
public:
    SortDialog(QWidget *parent = nullptr);
    ~SortDialog();
    void setColumnRange(QChar first,QChar last);
private:
    Ui::SortDialog *ui;
};
#endif // SORTDIALOG_H

main.cpp

#include "sortdialog.h"
#include <QApplication>

int main(int argc, char *argv[])
{   QApplication a(argc, argv);
    SortDialog *dialog = new SortDialog;
    dialog->setColumnRange('C','F');
    dialog->show();
    return a.exec();
}

sortdialog.cpp

#include "sortdialog.h"
#include "ui_sortdialog.h"
#include <QtGui>


SortDialog::SortDialog(QWidget *parent) :
    QDialog(parent),
    ui(new Ui::SortDialog)
{
    ui->setupUi(this);
    ui->secondaryGroupBox->hide();
    ui->tertiaryGroupBox->hide();
    layout()->setSizeConstraint(QLayout::SetFixedSize);

    setColumnRange('A','Z');

}
void SortDialog::setColumnRange(QChar first,QChar last)
{
    ui->primaryColumnCmbo->clear();
    ui->secondaryColumnCombo->clear();
    ui->tertiaryColumnCombo->clear();

    ui->secondaryColumnCombo->addItem(tr("None"));
    ui->tertiaryColumnCombo->addItem(tr("None"));

    ui->primaryColumnCombo->setMinimumSize(
                ui->secondaryColumnCombo->sizeHint());
    QChar ch = first;
    while (ch <= last){
        ui->primaryColumnCombo->addItem(QString(ch));
        ui->secondaryColumnCombo->addItem(QString(ch));
        ui->tertiaryColumnCombo->addItem(QString(ch));
        ch = ch.unicode() + 1;
    }
}
SortDialog::~SortDialog()
{
    delete ui;
}

sortdialog.ui

<?xml version="1.0" encoding="UTF-8"?>
<ui version="4.0">
 <class>secondaryGroupBox</class>
 <widget class="QDialog" name="secondaryGroupBox">
  <property name="geometry">
   <rect>
    <x>0</x>
    <y>0</y>
    <width>427</width>
    <height>468</height>
   </rect>
  </property>
  <property name="windowTitle">
   <string>Sort</string>
  </property>
  <widget class="QGroupBox" name="primaryGroupBox">
   <property name="geometry">
    <rect>
     <x>30</x>
     <y>30</y>
     <width>221</width>
     <height>131</height>
    </rect>
   </property>
   <property name="title">
    <string>&amp;Primary Key</string>
   </property>
   <widget class="QWidget" name="layoutWidget">
    <property name="geometry">
     <rect>
      <x>20</x>
      <y>30</y>
      <width>178</width>
      <height>51</height>
     </rect>
    </property>
    <layout class="QGridLayout" name="gridLayout">
     <item row="1" column="0">
      <widget class="QLabel" name="label_2">
       <property name="text">
        <string>Order:</string>
       </property>
      </widget>
     </item>
     <item row="0" column="2">
      <spacer name="horizontalSpacer">
       <property name="orientation">
        <enum>Qt::Horizontal</enum>
       </property>
       <property name="sizeHint" stdset="0">
        <size>
         <width>48</width>
         <height>18</height>
        </size>
       </property>
      </spacer>
     </item>
     <item row="0" column="0">
      <widget class="QLabel" name="label">
       <property name="text">
        <string>Column:</string>
       </property>
      </widget>
     </item>
     <item row="1" column="1" colspan="2">
      <widget class="QComboBox" name="primaryOrderCombo">
       <item>
        <property name="text">
         <string>Ascending</string>
        </property>
       </item>
       <item>
        <property name="text">
         <string>Descending</string>
        </property>
       </item>
      </widget>
     </item>
     <item row="0" column="1">
      <widget class="QComboBox" name="primaryColumnCombo">
       <item>
        <property name="text">
         <string>None</string>
        </property>
       </item>
      </widget>
     </item>
    </layout>
   </widget>
  </widget>
  <widget class="QGroupBox" name="groupBox_2">
   <property name="geometry">
    <rect>
     <x>30</x>
     <y>200</y>
     <width>221</width>
     <height>101</height>
    </rect>
   </property>
   <property name="title">
    <string>&amp;Secondary Key</string>
   </property>
   <widget class="QLabel" name="label_3">
    <property name="geometry">
     <rect>
      <x>20</x>
      <y>30</y>
      <width>62</width>
      <height>15</height>
     </rect>
    </property>
    <property name="text">
     <string>Column:</string>
    </property>
   </widget>
   <widget class="QLabel" name="label_4">
    <property name="geometry">
     <rect>
      <x>20</x>
      <y>60</y>
      <width>62</width>
      <height>15</height>
     </rect>
    </property>
    <property name="text">
     <string>Order:</string>
    </property>
   </widget>
   <widget class="QComboBox" name="secondaryColumnCombo">
    <property name="geometry">
     <rect>
      <x>90</x>
      <y>30</y>
      <width>71</width>
      <height>21</height>
     </rect>
    </property>
    <item>
     <property name="text">
      <string>None</string>
     </property>
    </item>
   </widget>
   <widget class="QComboBox" name="secondaryOrderCombo">
    <property name="geometry">
     <rect>
      <x>90</x>
      <y>60</y>
      <width>121</width>
      <height>21</height>
     </rect>
    </property>
    <item>
     <property name="text">
      <string>Ascending</string>
     </property>
    </item>
    <item>
     <property name="text">
      <string>Descending</string>
     </property>
    </item>
   </widget>
  </widget>
  <widget class="QGroupBox" name="tertiaryGroupBox">
   <property name="geometry">
    <rect>
     <x>30</x>
     <y>330</y>
     <width>221</width>
     <height>111</height>
    </rect>
   </property>
   <property name="title">
    <string>&amp;Tertiary Key</string>
   </property>
   <widget class="QLabel" name="label_5">
    <property name="geometry">
     <rect>
      <x>20</x>
      <y>30</y>
      <width>62</width>
      <height>15</height>
     </rect>
    </property>
    <property name="text">
     <string>Column:</string>
    </property>
   </widget>
   <widget class="QLabel" name="label_6">
    <property name="geometry">
     <rect>
      <x>20</x>
      <y>60</y>
      <width>62</width>
      <height>15</height>
     </rect>
    </property>
    <property name="text">
     <string>Order:</string>
    </property>
   </widget>
   <widget class="QComboBox" name="tertiaryColumnCombo">
    <property name="geometry">
     <rect>
      <x>90</x>
      <y>30</y>
      <width>71</width>
      <height>21</height>
     </rect>
    </property>
    <item>
     <property name="text">
      <string>None</string>
     </property>
    </item>
   </widget>
   <widget class="QComboBox" name="tertiaryOrderCombo">
    <property name="geometry">
     <rect>
      <x>90</x>
      <y>60</y>
      <width>121</width>
      <height>21</height>
     </rect>
    </property>
    <item>
     <property name="text">
      <string>Ascending</string>
     </property>
    </item>
    <item>
     <property name="text">
      <string>Descending</string>
     </property>
    </item>
   </widget>
  </widget>
  <widget class="QWidget" name="layoutWidget">
   <property name="geometry">
    <rect>
     <x>260</x>
     <y>30</y>
     <width>101</width>
     <height>131</height>
    </rect>
   </property>
   <layout class="QVBoxLayout" name="verticalLayout">
    <item>
     <widget class="QPushButton" name="okButton">
      <property name="text">
       <string>OK</string>
      </property>
      <property name="default">
       <bool>true</bool>
      </property>
     </widget>
    </item>
    <item>
     <widget class="QPushButton" name="cancelButton">
      <property name="text">
       <string>Cancel</string>
      </property>
     </widget>
    </item>
    <item>
     <spacer name="verticalSpacer">
      <property name="orientation">
       <enum>Qt::Vertical</enum>
      </property>
      <property name="sizeHint" stdset="0">
       <size>
        <width>20</width>
        <height>13</height>
       </size>
      </property>
     </spacer>
    </item>
    <item>
     <widget class="QPushButton" name="moreButton">
      <property name="text">
       <string>&amp;More</string>
      </property>
      <property name="checkable">
       <bool>true</bool>
      </property>
     </widget>
    </item>
   </layout>
  </widget>
 </widget>
 <layoutdefault spacing="6" margin="11"/>
 <resources/>
 <connections>
  <connection>
   <sender>okButton</sender>
   <signal>clicked()</signal>
   <receiver>secondaryGroupBox</receiver>
   <slot>accept()</slot>
   <hints>
    <hint type="sourcelabel">
     <x>320</x>
     <y>56</y>
    </hint>
    <hint type="destinationlabel">
     <x>192</x>
     <y>164</y>
    </hint>
   </hints>
  </connection>
 </connections>
</ui>