Python，Qt，ComboBox，两列？

Question

The question is quite simple, but as far there is a problem with the answer:

I'm using QT with Python and SQL. I'm getting some query data: 'select id, department from departments' I want to create combobox with two columns (id, department), which will display only "department" (department 1, department 2 .. etc), but after selecting, it should return "id".

In other words: i'm looking for same functionality as displaymember and valuemember for combobox in c#.

I managed to create a Qtableview in Combobox, but one problem creates another (view, reading "id" etc.). is there any other easier way?

Answer 1

As the OP notes that it uses QSqlTableModel, then a possible solution to mimic the behavior of C# is to establish the column that will be displayed through the modelColumn property, and then access the corresponding items (id and other fields) using the QSqlRecord associated with the selected row.

from PyQt5 import QtCore, QtWidgets, QtSql


def createConnection():
    db = QtSql.QSqlDatabase.addDatabase("QSQLITE")
    db.setDatabaseName(":memory:")
    if not db.open():
        QtWidgets.QMessageBox.critical(
            None,
            QtWidgets.qApp.tr("Cannot open database"),
            QtWidgets.qApp.tr(
                "Unable to establish a database connection.\n"
                "This example needs SQLite support. Please read "
                "the Qt SQL driver documentation for information "
                "how to build it.\n\n"
                "Click Cancel to exit."
            ),
            QtWidgets.QMessageBox.Cancel,
        )
        return False

    query = QtSql.QSqlQuery()
    query.exec_(
        "CREATE TABLE  Departments (id INTEGER PRIMARY KEY AUTOINCREMENT, department TEXT);"
    )

    query.exec_("INSERT INTO Departments(department) VALUES('department1')")
    query.exec_("INSERT INTO Departments(department) VALUES('department2')")
    query.exec_("INSERT INTO Departments(department) VALUES('department3')")
    query.exec_("INSERT INTO Departments(department) VALUES('department4')")
    query.exec_("INSERT INTO Departments(department) VALUES('department5')")
    return True


class Widget(QtWidgets.QWidget):
    def __init__(self, parent=None):
        super().__init__(parent)

        self.model = QtSql.QSqlTableModel(self)
        self.model.setTable("Departments")
        self.model.select()

        self.tableview = QtWidgets.QTableView()
        self.tableview.setModel(self.model)

        self.combo = QtWidgets.QComboBox()
        self.combo.setModel(self.model)
        column = self.model.record().indexOf("department")
        self.combo.setModelColumn(column)

        self.combo.currentIndexChanged.connect(self.onCurrentIndexChanged)

        lay = QtWidgets.QVBoxLayout(self)
        lay.addWidget(self.tableview)
        lay.addWidget(self.combo)

    @QtCore.pyqtSlot(int)
    def onCurrentIndexChanged(self, index):
        column = self.model.record().indexOf("id")
        r = self.model.record(index)
        value = r.value(column)
        print(value)


if __name__ == "__main__":
    import sys

    app = QtWidgets.QApplication(sys.argv)

    if not createConnection():
        sys.exit(1)

    w = Widget()
    w.show()

    sys.exit(app.exec_())

Another solution is that based on the data obtained by pyodbc you can build a QStandardItemModel (or another model) where the hidden field is associated with a role that can then be obtained.

from PyQt5 import QtCore, QtGui, QtWidgets

IdRole = QtCore.Qt.UserRole + 1000


class Widget(QtWidgets.QWidget):
    def __init__(self, parent=None):
        super().__init__(parent)

        d = (
            (1, "department1"),
            (2, "department2"),
            (3, "department3"),
            (4, "department4"),
            (5, "department5"),
        )

        self.model = QtGui.QStandardItemModel(self)

        for id_, value in d:
            it = QtGui.QStandardItem(value)
            it.setData(id_, IdRole)
            self.model.appendRow(it)

        self.combo = QtWidgets.QComboBox()
        self.combo.setModel(self.model)

        self.combo.currentIndexChanged.connect(self.onCurrentIndexChanged)

        lay = QtWidgets.QVBoxLayout(self)
        lay.addWidget(self.combo)

    @QtCore.pyqtSlot(int)
    def onCurrentIndexChanged(self, index):
        id_ = self.combo.itemData(index, IdRole)
        # or
        # id_ = self.model.item(index).data(IdRole)
        print(id_)


if __name__ == "__main__":
    import sys

    app = QtWidgets.QApplication(sys.argv)

    w = Widget()
    w.show()

    sys.exit(app.exec_())