如果可用，委托默认使用 BackgroundRole 信息，因此解决方案只是返回 QColor、QBrush 或类似信息.

The delegate by default uses the BackgroundRole information if it is available so the solution is just to return a QColor, QBrush or similar.

from PySide2 import QtCore, QtGui

class PandasModel2(QtCore.QAbstractTableModel):
    # ...
    def data(self, index, role=QtCore.Qt.DisplayRole):
        if not index.isValid():
            return
        if not (0 <= index.row() < self.rowCount() and 0 <= index.column() <= self.columnCount()):
            return
        value = self._data.iloc[index.row(), index.column()]
        if role == QtCore.Qt.DisplayRole:
            if index.column() != 4: 
                if index.column() in [1,2,3]:
                    return '{:.3f}'.format(value)    
                if index.column() == 0:
                    return '{:.2f}'.format(value)
                return str(value)
        elif role == QtCore.Qt.CheckStateRole:  
            if index.column() == 4:
                return QtCore.Qt.Checked if value else QtCore.Qt.Unchecked
        elif index.column() == self.getColumnNumber('MEASURED'):
            if role == QtCore.Qt.BackgroundRole:
                if self.getMinimum(index.row()) <= value <= self.getMaximum(index.row()):
                    return QtGui.QColor("red")