QAbstractTableModel读取数据以及QStyleItemDelegate修改数据

　　使用QStyleItemDelegate修改数据， 官网有QSpinBox例子，这里使用QComboBox
　　h头文件Class ClassMaterDelegate : public QStyleItemDelegate {     Q_OBJECT  public:     ClassMaterDelegate(QObject* parent = nullptr);     ~ClassMaterDelegate();      QWidget *createEditor(QWidget *parent, const QStyleOptionViewItem &option,                             const QModelIndex &index) const override;      void setEditorData(QWidget *editor, const QModelIndex &index) const override;     void setModelData(QWidget *editor, QAbstractItemModel *model,                         const QModelIndex &index) const override;       };
　　cpp实现文件ClassMaterDelegate::ClassMaterDelegate(QObject* parent) : QStyleItemDelegate(parent) {  } ClassMaterDelegate::~ClassMaterDelegate()  {  }  QWidget* ClassMaterDelegate::createEditor(QWidget *parent, const QStyleOptionViewItem &option, const QModelIndex &index) const {     if (!index.isValid())     {         return QStyleItemDelegate::createEditor(parent, option, index);     }     QComboBox* pComboBox = new QComboBox(parent);     std::vector classMaters = ClassMater::GetAll();     for (auto it = classMaters.begin(); it != classMaters.end(); ++it)     {         pComboBox->addItem(it->getName(), it->getId());     }     return pComboBox; }  void ClassMaterDelegate::setEditorData(QWidget *editor, const QModelIndex &index) const {     if (!index.isValid())     {         return ;     }      QString qtrName = index.model()->data(index, Qt::EditRole).toString();     QComboBox* pComboBox = static_cast(editor);     int cmbIndex = pComboBox->findText(qtrName);     pComboBox->setCurrentIndex(cmbIndex); }  void ClassMaterDelegate::setModelData(QWidget *editor, QAbstractItemModel *model, const QModelIndex &index) const {     if (!index.isValid())     {         return ;     }      QComboBox* pComboBox = static_cast(editor);     QString qtrName = pComboBox->currentText();     model->setData(index, qtrName, Qt::EditRole); }
　　使用QAbstractTableModel读取和修改数据
　　h头文件class StudentModel : public QAbstractTableModel  { public:     StudentModel(Qobject* parent = nullptr);     ~StudentModel();      void getAll();     const Student& getOne(int row) const;     void addStudent();     void deleteStudent(int row);      int rowCount(const QModelIndex &parent = QModelIndex()) const override;     int columnCount(const QModelIndex &parent = QModelIndex()) const override;      QVariant data(const QModelIndex &index, int role = Qt::DisplayRole) const override;     QVariant headerData(int section, Qt::Orientation orientation, int role = Qt::DisplayRole) const override;     bool setData(const QModelIndex &index, const QVariant &value, int role = Qt::EditRole) override;     Qt::ItemFlags flags(const QModelIndex &index) const override;  private:     std::vector vecStrHeaders =  {＂姓名＂, ＂班级＂, ＂年龄＂};     std::vector vecStudents; };
　　cpp实现文件StudentModel::StudentModel(Qobject* parent) : QAbstractTableModel(parent) {  } StudentModel::~StudentModel {  }  StudentModel::void getAll() {     beginResetModel();     vecStudents = Student::getAll();     endResetModel(); }  const Student& StudentModel::getOne(int row) const {     const Student& stu = vecStudents[row];     return stu; }  void StudentModel::addStudent() {     Student stu;     stu.setName(＂test＂)     stu.setClassMater(1);     stu.setAge(18);      if (!Student::add(stu))     {         return;     }      beginInsertRows(QModelIndex(), 0, 0);     vecStudents.insert(vecStudents.begin(), stu);     endInsertRows(); }  void StudentModel::deleteStudent(int row) {     const Student& stu = vecStudents[row];     if (!Student::delete(stu.getId()))     {         return;     }      auto it = vecStudents.begin();     std::advance(it, row);     beginRemoveRows(QModelIndex(), row, row);     vecStudents.erase(it);     endRemoveRows(); }  int StudentModel::rowCount(const QModelIndex &parent = QModelIndex()) const {     return vecStudents.size(); }  int StudentModel::columnCount(const QModelIndex &parent = QModelIndex()) const {     return vecStrHeaders.size(); }  QVariant StudentModel::data(const QModelIndex &index, int role) const {     if (!index.isValid())     {         return QVariant();     }      if (role == Qt::DisplayRole || role == Qt::EditRole)     {         const Student& stu = vecStudents[index.row()];         switch(index.column())         {         case 0:             return stu.getName();         case 1:             return stu.getClassMater();         case 2:             return sty.getAge();         default:             return QVariant();         }     }     return QVariant(); }  QVariant StudentModel::headerData(int section, Qt::Orientation orientation, int role = Qt::DisplayRole) const {     if (!index.isValid())     {         return QVariant();     }      if (role == Qt::DisplayRole)     {         if (orientation == Qt::Horizontal)         {             return vecStrHeaders[section];         }     }     return QVariant();  }  bool StudentModel::setData(const QModelIndex &index, const QVariant &value, int role = Qt::EditRole) {     if (!index.isValid())     {         return QVariant();     }      if (index.column() == 1 && role == Qt::EditRole)     {         ClassMater classMater;         bool success = ClassMater::getByName(value.toString(), classMater);         if (!success)         {             return false;         }          Student& stu = vecStudents[index.row()];         stu.setClassMater(classMater.getId());         bool hasSave = Student::update(stu);         if (hasSave)         {             this->getAll();         }         return hasSave;     }     return false; }  Qt::ItemFlags StudentModel::flags(const QModelIndex &index) const {     if (!index.isValid())     {         return QVariant();     }     if (index.column() == 1)     {         return Qt::ItemIsSelectable | Qt::ItemIsEditable | Qt::ItemIsEnabled;     }     return Qt::ItemIsSelectable | Qt::ItemIsEnabled; }
　　使用ui->studentList->setItemDelegateForColumn(1, new ClassMaterDelegate(this)); ui->studentList->setModel(mModel); // 头文件定义 StudentModel mModel; //设置最后一列自适应 ui->studentList->horizontalHeader()->setStretchLastSection(true); //设置选择的行为： 选择整行 ui->studentList->setSelectionBehavior(QAbstractItemView::SelectRows); //设置选择的模式： 单选模式，即只能选中一行 ui->studentList->setSelectionMode(QAbstractItemView::SingleSelection);