pyqt5 组合框选定的项目与另一个窗口共享（信号/插槽）

Question

I am trying to get Qcombobox selected variable data from onewindow.py to anotherWindow.py. i am stuck when i use signal/slot mechanism.

i have two files mainWindow.py and connection.py , in mainWindow i have a combobox where user can choose a server, i want, when user choose a server from combobox then then selected item(variable) will be sent to the connection.py

mainwindow.py:

from PyQt5 import QtCore, QtGui, QtWidgets


class ui_MainWindow(object):
    def setupUi(self, MainWindow):
        MainWindow.setObjectName("MainWindow")
        MainWindow.resize(800, 600)
        self.centralwidget = QtWidgets.QWidget(MainWindow)
        self.centralwidget.setObjectName("centralwidget")
        self.comboBox = QtWidgets.QComboBox(self.centralwidget)
        self.comboBox.setGeometry(QtCore.QRect(310, 230, 151, 22))
        self.comboBox.setObjectName("comboBox")
        self.comboBox.addItem("")
        self.comboBox.addItem("")
        self.label = QtWidgets.QLabel(self.centralwidget)
        self.label.setGeometry(QtCore.QRect(310, 300, 281, 20))
        self.label.setObjectName("label")
        MainWindow.setCentralWidget(self.centralwidget)
        self.statusbar = QtWidgets.QStatusBar(MainWindow)
        self.statusbar.setObjectName("statusbar")
        MainWindow.setStatusBar(self.statusbar)

        self.retranslateUi(MainWindow)
        QtCore.QMetaObject.connectSlotsByName(MainWindow)
        # combobox selected
        self.comboBox.activated[str].connect(self.onChanged)


    def retranslateUi(self, MainWindow):
        _translate = QtCore.QCoreApplication.translate
        MainWindow.setWindowTitle(_translate("MainWindow", "MainWindow"))
        self.comboBox.setItemText(0, _translate("MainWindow", "TFUS3"))
        self.comboBox.setItemText(1, _translate("MainWindow", "TFUSD"))
        self.label.setText(_translate("MainWindow", "TextLabel"))

    #-----------
    def onChanged(self,text):
        self.label.setText(text)
        message=text
        return message

if __name__ == "__main__":
    import sys
    app = QtWidgets.QApplication(sys.argv)
    MainWindow = QtWidgets.QMainWindow()
    ui = ui_MainWindow()
    ui.setupUi(MainWindow)
    MainWindow.show()
    sys.exit(app.exec_())

and connection.py

 from PyQt5 import QtCore, QtGui, QtWidgets
    from PyQt5.QtSql import QSqlDatabase, QSqlQuery, QSqlQueryModel
    from PyQt5.QtWidgets import QTableView, QApplication
    import mainWindow
    from mainWindow import *

    class Example(QWidget):

        def get_value(self,text):
        message=text
        print(message)

        def __init__(self):
            super().__init__()

            self.initUI()

        def initUI(self):      

            self.lbl = QLabel("select server from mainwindow is:",self )

            self.setGeometry(300, 300, 300, 200)
            self.setWindowTitle('QComboBox')
            self.show()


        def onActivated(self, text):


            createConnection(self,text)
            self.lbl.adjustSize()  


    ------server part----------------------------
    USERNAME = 'XXXXXX'
    PASSWORD = '000000'

    def selectedServer(server):
        switcher ={
            'Server1': 'x.x.x.x,1433',
            'Server2': 'x.x.x.x,1433',
        }
        return switcher.get(server,"Invalid Server ")

    def createConnection(self,server):


        SERVER= selectedServer(server)

        global db
        db = QSqlDatabase.addDatabase('QODBC')
        db.setDatabaseName(f'Driver={{SQL SERVER}}; Server={SERVER}; UID={USERNAME}; PWD={PASSWORD}')
        if db.open():
            self.lbl.setText(f'{server} Server connected successfully')
            print(f'{server} Server connected successfully')

        else:
            print('connection failed')


    if __name__ == '__main__':

        app = QApplication(sys.argv)
        ex = Example()
        sys.exit(app.exec_())

i tried many time to show selected server in textlabe in connection window.but failed. don't know where i did mistake.

Answer 1

First of all it must be clear that information is not sent between files but between objects, the application is not the files but the interaction between the objects or other elements that are described in the source code(files).

On the other hand you should not modify the code generated by Qt Designer so you will have to restore the mainWindow.py file.

Considering the above, an instance of each class must be created (in the case of Ui_MainWindow it is better to create a new class that inherits from the appropriate widget and use Ui_MainWindow to fill it). And then there make the connection between the components.

connection.py

import sys
from PyQt5 import QtCore, QtGui, QtWidgets, QtSql


USERNAME = "XXXXXX"
PASSWORD = "000000"


def selectedServer(server):
    switcher = {
        "Server1": "x.x.x.x,1433",
        "Server2": "x.x.x.x,1433",
    }
    return switcher.get(server, "Invalid Server ")


class Example(QtWidgets.QWidget):
    def __init__(self):
        super().__init__()
        self.initUI()

    def initUI(self):
        self.lbl = QtWidgets.QLabel("select server from mainwindow is:", self)

        self.setGeometry(300, 300, 300, 200)
        self.setWindowTitle("QComboBox")

    def setServer(self, name):
        self.createConnection(name)
        self.lbl.adjustSize()

    def createConnection(self, server):
        SERVER = selectedServer(server)
        db = QtSql.QSqlDatabase.addDatabase("QODBC")
        db.setDatabaseName(
            f"Driver={{SQL SERVER}}; Server={SERVER}; UID={USERNAME}; PWD={PASSWORD}"
        )
        if db.open():
            self.lbl.setText(f"{server} Server connected successfully")
            self.lbl.adjustSize()
            print(f"{server} Server connected successfully")

        else:
            print("connection failed")


if __name__ == "__main__":

    app = QtWidgets.QApplication(sys.argv)
    ex = Example()
    ex.show()
    sys.exit(app.exec_())

main.py

import sys

from PyQt5 import QtWidgets

from mainWindow import ui_MainWindow
from connection import Example


class MainWindow(QtWidgets.QMainWindow, ui_MainWindow):
    def __init__(self, parent=None):
        super().__init__(parent)
        self.setupUi(self)


if __name__ == "__main__":

    app = QtWidgets.QApplication(sys.argv)
    w = MainWindow()
    w.show()
    ex = Example()
    ex.show()

    w.comboBox.currentTextChanged.connect(ex.setServer)
    sys.exit(app.exec_())