如何从 SQL 填充 Combobox 数据？使用 Python

Question

（图 1）- 这是我的简单程序的输出，据说它有 5 个来自数据库的下拉项，但它只显示 1 个数据，这是已读取的数据库的最后一行。

图片1-

（图 2）- 这是代码，我使用 for 循环，我希望它循环并显示 db 中的每个数据，但它只显示最后一行。是语法错误还是逻辑错误？

# Combobox - Subjects
self.cbSubjects = ttk.Combobox(root, width=17, textvariable=self.cbSubjects)
self.cbSubjects.place(x=120, y=60)

# SQL Command
self.conn = cx_Oracle.connect('system/system@127.0.0.1/xe')
self.cursor = self.conn.cursor()
self.cursor.execute("SELECT hr.subject.description FROM hr.subject")
for i in self.cursor:

   self.cbSubjects['values'] = (i)
   self.cbSubjects.current(0)

self.cursor.close()
self.conn.close()

（图 3）- 这是我想在 Combobox 上显示的 SQL 数据

图3-

我是 Python tkinter 的新手。非常感谢！

Answer 1

在for 循环中，您只是覆盖了组合框中的单个值，为什么会执行此行：self.cbSubjects['values'] = (i)。您为其分配的最后一个值是SELECT SQL 语句返回的最后一行。所以这就是你遇到这个问题的原因的解释。

对于解决方案，如果您查看通常是您最好的朋友的documentation，您可以阅读以下内容：

values 指定要在下拉列表中显示的值列表 列表框。

实际上这有点误导，因为self.cbSubjects['values'] 是一个元组，而不是一个列表，而且你知道元组是不可变的，不像列表，但你仍然可以通过让i 穿着衣服来克服这个问题具有一个元素的元组。

也许通过代码，你会更好地理解这个想法：

#...
for i in self.cursor:   
   # self.cbSubjects['values'] = (i) , this is bad, change it like this:
   self.cbSubjects['values'] = self.cbSubjects['values'] + (i, )
   # ... rest of your program

Answer 2

# -*- coding: utf-8 -*-

# Form implementation generated from reading ui file 'delivery.ui'
#
# Created by: PyQt5 UI code generator 5.14.1
#
# WARNING! All changes made in this file will be lost!


from PyQt5 import QtCore, QtGui, QtWidgets
import sqlite3
conn = sqlite3.connect("spmanager.db")
cursor = conn.cursor()


class Ui_Form(object):
    def setupUi(self, Form):
        Form.setObjectName("Form")
        Form.resize(773, 621)
        self.label = QtWidgets.QLabel(Form)
        self.label.setGeometry(QtCore.QRect(310, 20, 121, 20))
        font = QtGui.QFont()
        font.setFamily("Ubuntu Condensed")
        font.setPointSize(12)
        font.setBold(True)
        font.setWeight(75)
        self.label.setFont(font)
        self.label.setObjectName("label")
        self.verticalLayoutWidget = QtWidgets.QWidget(Form)
        self.verticalLayoutWidget.setGeometry(QtCore.QRect(50, 210, 701, 331))
        self.verticalLayoutWidget.setObjectName("verticalLayoutWidget")
        self.verticalLayout = QtWidgets.QVBoxLayout(self.verticalLayoutWidget)
        self.verticalLayout.setContentsMargins(0, 0, 0, 0)
        self.verticalLayout.setObjectName("verticalLayout")
        self.tableWidget = QtWidgets.QTableWidget(self.verticalLayoutWidget)
        self.tableWidget.setObjectName("tableWidget")
        self.tableWidget.setColumnCount(3)
        self.tableWidget.setRowCount(1)
        item = QtWidgets.QTableWidgetItem()
        self.tableWidget.setVerticalHeaderItem(0, item)
        item = QtWidgets.QTableWidgetItem()
        self.tableWidget.setHorizontalHeaderItem(0, item)
        item = QtWidgets.QTableWidgetItem()
        self.tableWidget.setHorizontalHeaderItem(1, item)
        item = QtWidgets.QTableWidgetItem()
        self.tableWidget.setHorizontalHeaderItem(2, item)
        self.verticalLayout.addWidget(self.tableWidget)
        self.frame_3 = QtWidgets.QFrame(Form)
        self.frame_3.setGeometry(QtCore.QRect(40, 550, 331, 80))
        self.frame_3.setFrameShape(QtWidgets.QFrame.StyledPanel)
        self.frame_3.setFrameShadow(QtWidgets.QFrame.Raised)
        self.frame_3.setObjectName("frame_3")
        self.label_4 = QtWidgets.QLabel(self.frame_3)
        self.label_4.setGeometry(QtCore.QRect(0, 0, 91, 17))
        self.label_4.setObjectName("label_4")
        self.textEdit = QtWidgets.QTextEdit(self.frame_3)
        self.textEdit.setGeometry(QtCore.QRect(10, 19, 291, 61))
        self.textEdit.setObjectName("textEdit")
        self.layoutWidget = QtWidgets.QWidget(Form)
        self.layoutWidget.setGeometry(QtCore.QRect(50, 70, 691, 91))
        self.layoutWidget.setObjectName("layoutWidget")
        self.gridLayout = QtWidgets.QGridLayout(self.layoutWidget)
        self.gridLayout.setContentsMargins(0, 0, 0, 0)
        self.gridLayout.setObjectName("gridLayout")
        self.frame_2 = QtWidgets.QFrame(self.layoutWidget)
        self.frame_2.setFrameShape(QtWidgets.QFrame.StyledPanel)
        self.frame_2.setFrameShadow(QtWidgets.QFrame.Raised)
        self.frame_2.setObjectName("frame_2")
        self.label_3 = QtWidgets.QLabel(self.frame_2)
        self.label_3.setGeometry(QtCore.QRect(10, 30, 67, 17))
        self.label_3.setObjectName("label_3")
        self.dateEdit = QtWidgets.QDateEdit(self.frame_2)
        self.dateEdit.setGeometry(QtCore.QRect(70, 20, 151, 41))
        self.dateEdit.setObjectName("dateEdit")
        self.gridLayout.addWidget(self.frame_2, 0, 1, 1, 1)
        self.frame = QtWidgets.QFrame(self.layoutWidget)
        self.frame.setFrameShape(QtWidgets.QFrame.StyledPanel)
        self.frame.setFrameShadow(QtWidgets.QFrame.Raised)
        self.frame.setObjectName("frame")
        self.label_2 = QtWidgets.QLabel(self.frame)
        self.label_2.setGeometry(QtCore.QRect(20, 30, 71, 21))
        self.label_2.setObjectName("label_2")
        self.comboBox = QtWidgets.QComboBox(self.frame)
        self.comboBox.setGeometry(QtCore.QRect(80, 30, 171, 25))
        self.comboBox.setEditable(True)
        self.comboBox.setObjectName("comboBox")
        self.comboBox.addItem("")
        #list1 = ['First Item','Second Item','Third Item']
        #self.comboBox.addItems(list1)

        self.gridLayout.addWidget(self.frame, 0, 0, 1, 1)
        self.frame_4 = QtWidgets.QFrame(Form)
        self.frame_4.setGeometry(QtCore.QRect(540, 540, 181, 81))
        self.frame_4.setFrameShape(QtWidgets.QFrame.StyledPanel)
        self.frame_4.setFrameShadow(QtWidgets.QFrame.Raised)
        self.frame_4.setObjectName("frame_4")
        self.comboBox_2 = QtWidgets.QComboBox(self.frame_4)
        self.comboBox_2.setGeometry(QtCore.QRect(5, 20, 141, 25))
        self.comboBox_2.setObjectName("comboBox_2")
        self.comboBox_2.addItem("")
        self.comboBox_2.addItem("")
        self.comboBox_2.addItem("")
        self.comboBox_2.addItem("")
        self.pushButton = QtWidgets.QPushButton(self.frame_4)
        self.pushButton.setGeometry(QtCore.QRect(8, 50, 131, 25))
        self.pushButton.setObjectName("pushButton")

        self.retranslateUi(Form)
        QtCore.QMetaObject.connectSlotsByName(Form)


        def customer_names(self):
            self.conn = conn
            self.cursor = cursor
            self.cursor.execute("SELECT  customer_name FROM customers ORDER BY customer_name")
            self.sql =cursor.fetchall()
        customer_names(self)
        self.names =[]
        for i in self.sql:
            self.names.append(i[0])
        self.comboBox.addItems(self.names)



    def retranslateUi(self, Form):
        _translate = QtCore.QCoreApplication.translate
        Form.setWindowTitle(_translate("Form", "HI-SPECS INNOVATIVE DELIVERY NOTE"))
        self.label.setText(_translate("Form", "DELIVERY NOTE"))
        item = self.tableWidget.verticalHeaderItem(0)
        item.setText(_translate("Form", "1"))
        item = self.tableWidget.horizontalHeaderItem(0)
        item.setText(_translate("Form", "Qnty"))
        item = self.tableWidget.horizontalHeaderItem(1)
        item.setText(_translate("Form", "Item"))
        item = self.tableWidget.horizontalHeaderItem(2)
        item.setText(_translate("Form", "Description"))
        self.label_4.setText(_translate("Form", "Comment"))
        self.label_3.setText(_translate("Form", "Date:"))
        self.label_2.setText(_translate("Form", "Name:"))
        self.comboBox.setItemText(0, _translate("Form", "customer"))
        self.comboBox_2.setItemText(0, _translate("Form", "Print & Record"))
        self.comboBox_2.setItemText(1, _translate("Form", "Print"))
        self.comboBox_2.setItemText(2, _translate("Form", "Record"))
        self.comboBox_2.setItemText(3, _translate("Form", "Email"))
        self.pushButton.setText(_translate("Form", "Continue"))


if __name__ == "__main__":
    import sys
    app = QtWidgets.QApplication(sys.argv)
    Form = QtWidgets.QWidget()
    ui = Ui_Form()
    ui.setupUi(Form)
    Form.show()
    sys.exit(app.exec_())