在designer.exe中设置pyside2的 QComboBox的item样式

可以使用QStyledItemDelegate来设置QComboBox的item样式，具体实现可以参考以下代码：

from PySide2.QtWidgets import QComboBox, QApplication, QStyledItemDelegate
from PySide2.QtGui import QPainter, QColor, QBrush, QFontMetrics
from PySide2.QtCore import Qt, QRect

class ItemDelegate(QStyledItemDelegate):
    def paint(self, painter, option, index):
        if option.state & QStyle.State_Selected:
            painter.fillRect(option.rect, option.palette.highlight())
        else:
            painter.fillRect(option.rect, option.palette.base())
        painter.drawText(option.rect, Qt.AlignCenter, index.data())

class ComboBox(QComboBox):
    def __init__(self, parent=None):
        super().__init__(parent)
        self.setItemDelegate(ItemDelegate(self))

if __name__ == '__main__':
    app = QApplication([])
    combo = ComboBox()
    combo.addItems(['item1', 'item2', 'item3'])
    combo.show()
    app.exec_()

这段代码使用QStyledItemDelegate来绘制QComboBox的item，可以自定义item的样式。