editor/mylistwidget.h

#ifndef MYLISTWIDGET_H
#define MYLISTWIDGET_H
#include <QDrag>
#include <QListWidget>
#include <QMimeData>

class MyListWidget : public QListWidget {
public:
    using QListWidget::QListWidget;

protected:
    void startDrag(Qt::DropActions supportedActions) override
    {
        QListWidgetItem *item = currentItem();
        if (!item) return;

        QDrag *drag = new QDrag(this);
        QMimeData *mimeData = new QMimeData;

        QString type = item->data(Qt::UserRole).toString();
        mimeData->setData("application/x-component", type.toUtf8());
        drag->setMimeData(mimeData);

        drag->setPixmap(item->icon().pixmap(iconSize()));
        drag->setHotSpot(drag->pixmap().rect().center());

        drag->exec(Qt::CopyAction);
    }
};

#endif // MYLISTWIDGET_H