如何在for循环中强制执行多个QComboBox中的任何一个的最小索引？

我有一个QWizard，它读取CSV文件的列标题并使用户选择他们想要的每一列。在此向导的第二页中，我将组合框添加到for循环中，该循环遍历CSV的列名。所有组合框均为必填字段。但是，另一个限制是，在用户可以按“下一步”之前，必须至少选择其中一个来选择3或更高（在我的MWE中为c1或c2）。

除了self.NextButton.setEnabled（False）之外，我还根据此示例和此问题尝试使用isComplete和completeChanged，但由于是PyQt的初学者并且不太擅长C ++，所以我没有能够了解很多现有文档。目前，isComplete似乎还可以，但是向导未在注册它。

谁能教我如何实现我想要的目标（粗体文字）？

from PyQt5 import QtGui, QtWidgets, QtCore
import csv

class ChooseFile(QtWidgets.QWizardPage):

    def __init__(self, parent=None):
        super(ChooseFile, self).__init__(parent)

        body = QtWidgets.QVBoxLayout()

        self.filePathShow = QtWidgets.QLineEdit(self)
        self.filePathShow.setReadOnly(True)                      # not editable
        self.registerField("filePathShow\*, self.filePathShow)   # mandatory
        body.addWidget(self.filePathShow)

        browseButton = QtWidgets.QPushButton('Browse...', self)
        browseButton.clicked.connect(self.browseDialog)
        browseBox = QtWidgets.QHBoxLayout()
        browseBox.addWidget(browseButton)
        body.addLayout(browseBox)

        self.setLayout(body)

    def browseDialog(self):
        filePath, _ = QtWidgets.QFileDialog.getOpenFileName(self, 'Open CSV', '/home', '(\*csv)')
        if filePath:   # only changes if valid file, stays the same if user presses cancel
            self.setField("filePathShow", filePath)

class ChooseColumns(QtWidgets.QWizardPage):

    def __init__(self, parent=None):
        super(ChooseColumns, self).__init__(parent)

        self.box = QtWidgets.QGroupBox()
        body = QtWidgets.QVBoxLayout()
        body.addWidget(self.box)   # these are where the choices (comboboxes) go
        self.setLayout(body)


    def initializePage(self):
        filePath2 = self.field("filePathShow")
        with open(str(filePath2), 'r') as f:
            reader = csv.reader(f)
            self.columns = next(reader)            
            # make a combobox for each column
            grid = QtWidgets.QGridLayout()
            self.comboBoxes = [None] * len(self.columns)
            for i, col in enumerate(self.columns):
                grid.addWidget(QtWidgets.QLabel(col), i, 0)   # printscolumn name

                self.comboBoxes[i] = QtWidgets.QComboBox()
                self.comboBoxes[i].addItem("")         # default value since is mandatory field
                self.comboBoxes[i].addItem("a")
                self.comboBoxes[i].addItem("b")
                self.comboBoxes[i].addItem("c1")
                self.comboBoxes[i].addItem("c2")

                grid.addWidget(self.comboBoxes[i], i, 1)
                self.registerField("column" + str(i) + "\*, self.comboBoxes[i]) # all mandatory
                self.comboBoxes[i].currentIndexChanged.connect(self.isComplete)
                #self.connect(self.comboBoxes[i], QtCore.SIGNAL(currentIndexChanged()), 
                #            self, QtCore.SIGNAL(completeChanged()))
                self.comboBoxes[i].currentIndexChanged.connect(self.completeChanged)   # DOESN'T WORK
            self.box.setLayout(grid)

    def isComplete(self, other):   # WORKS
        self.selections = [None] * len(self.columns)
        for i in range(len(self.selections)):   # first fill the list
            self.selections[i] = self.comboBoxes[i].currentIndex()
        #print(self.selections)
        for item in self.selections:   # then evaluate the values
            if i >= 3:
                return True
        return False


class Manager(QtWidgets.QWizard):

    def __init__(self, parent=None):
        super(Manager, self).__init__(parent)

        self.resize(500, 300)

        self.addPage(ChooseFile(self))
        self.addPage(ChooseColumns(self))


if __name__ == '__main__':
    import sys
    app = QtWidgets.QApplication(sys.argv)
    w = Manager()
    w.show()
    sys.exit(app.exec_())

问题来源：stackoverflow