[PyQt] PyQt4 dynamic QComboBox

[Alfalfa]

The combo is not shown because it (self.dd) is not added to the layout. You should subclass QComboBox directly instead of QWidget, unless you really need QWidget methods.

#!/usr/bin/python3
import sys
from PyQt5 import QtCore, QtGui, QtWidgets

class Main(QtWidgets.QMainWindow):
    def __init__(self, parent):
        super().__init__()
        self.ui = QtWidgets.QWidget(self)
        self.setCentralWidget(self.ui)
        self.ui.combo = PartRoleComboBox()
        self.ui.layout = QtWidgets.QVBoxLayout()
        self.ui.layout.addWidget(self.ui.combo)
        self.ui.setLayout(self.ui.layout)
        self.show()

        def add_part_role_dropdown(self):
            # Add a dropdown control containing list of part roles
            obj_name = "ddnSection" + str(self.section)
            dd = prCombo(self.form, obj_name)
            self.gridLayout.addWidget(dd, self.section+4, 1, 1, 1, QtCore.Qt.AlignHCenter)

class PartRoleComboBox(QtWidgets.QComboBox):

    def __init__(self):
        QtWidgets.QWidget.__init__(self)
        #self.parent_form = form
        self.available_options = ['Hardware', 'Base', 'Case', 'Drawer']
        self.addItems(self.available_options)
        self.currentIndexChanged.connect(self.part_role_selection_changed)
        ##self.setObjectName(object_name)
        # dd.setToolTip("Choose a part role to configure", None)
        self.sizeHint()

    def part_role_selection_changed(self):
        print("dropdown selection changed")
        print(self.currentText())
        #self.parent_form.add_part_role_shadows_table(self.currentText())


if __name__== '__main__':
    app = QtWidgets.QApplication([])
    gui = Main(app)
    sys.exit(app.exec_())