QComboBox实现复选功能（三种方法：嵌套QListWidget, 设置QStandardItemModel, 设置Delegate）

1. 下拉列表有复选功能
2. 不可编辑
3. 显示所有选中项

1. QStandardItemModel + QStandardItem
2. QListWidget + QListWidgetItem
3. Model/View + QItemDelegate

    pListWidget = new QListWidget(this);
        pLineEdit = new QLineEdit(this);
        for (int i = 0; i < 5; ++i)
    {
        QListWidgetItem *pItem = new QListWidgetItem(pListWidget);
        pListWidget->addItem(pItem);
        pItem->setData(Qt::UserRole, i);
        QCheckBox *pCheckBox = new QCheckBox(this);
        pCheckBox->setText(QStringLiteral("Qter%1").arg(i));
        pListWidget->addItem(pItem);
        pListWidget->setItemWidget(pItem, pCheckBox);
        connect(pCheckBox, SIGNAL(stateChanged(int)), this, SLOT(stateChanged(int)));
    }
        ui.comboBox->setModel(pListWidget->model());
        ui.comboBox->setView(pListWidget);
        ui.comboBox->setLineEdit(pLineEdit);
        pLineEdit->setReadOnly(true);                                                                                                                    //ui.comboBox->setEditable(true);
        connect(pLineEdit, SIGNAL(textChanged(const QString &)), this, SLOT(textChanged(const QString &)));

void MultiComboBox::stateChanged(int state)
{
        bSelected = true;
        QString strSelectedData("");
        strSelectedText.clear();
    QObject *object = QObject::sender();
    QCheckBox *pSenderCheckBox = static_cast(object);
    int nCount = pListWidget->count();
    for (int i = 0; i < nCount; ++i)
    {
        QListWidgetItem *pItem = pListWidget->item(i);
        QWidget *pWidget = pListWidget->itemWidget(pItem);
                QCheckBox *pCheckBox = (QCheckBox *)pWidget;
                if (pCheckBox->isChecked())
                {
                        QString strText = pCheckBox->text();
                        strSelectedData.append(strText).append(";");
                }
                //所点击的复选框
        if (pSenderCheckBox == pCheckBox)
        {
                        int nData = pItem->data(Qt::UserRole).toInt();
            qDebug() << QString("I am sender...id : %1").arg(nData);
        }
    }
    if (strSelectedData.endsWith(";"))
        strSelectedData.remove(strSelectedData.count() - 1, 1);
    if (!strSelectedData.isEmpty())
    {
                //ui.comboBox->setEditText(strSelectedData);
                strSelectedText = strSelectedData;
        pLineEdit->setText(strSelectedData);
        pLineEdit->setToolTip(strSelectedData);
    }
        else
        {
                pLineEdit->clear();
                //ui.comboBox->setEditText("");
        }
        bSelected = false;
}

void MultiComboBox::textChanged(const QString &text)
{
        if (!bSelected)
                pLineEdit->setText(strSelectedText);
}

转载自：╰☆一去?二三里`

另外关于QCOmbobox的扩展，请点击：QCompleter自动补全、Qt之QComboBox（基本应用、代理设置）