QComboBox 点击事件 [英] QComboBox click event

问题描述

我一直试图在 PyQt5 中获取一个 QComboBox 以从数据库表中填充.问题是试图找到一种方法来识别点击事件.

I have been trying to get a QComboBox in PyQt5 to become populated from a database table. The problem is trying to find a method that recognizes a click event on it.

在我的 GUI 中，我的组合框最初是空的，但是在单击它时，我希望单击事件激活我的方法以与数据库通信并填充下拉列表.到目前为止，组合框的点击事件似乎没有内置的事件处理程序.我希望我错了.我希望有人能够告诉我有一种方法可以做到这一点.

In my GUI, my combo-box is initially empty, but upon clicking on it I wish for the click event to activate my method for communicating to the database and populating the drop-down list. It seems so far that there is no built-in event handler for a click-event for the combo-box. I am hoping that I am wrong on this. I hope someone will be able to tell me that there is a way to do this.

我能在这里找到的关于我的用例的最好的文章来自这个链接，引用了 PyQt4 QComboBox:

The best article I could find on my use-case here is from this link referring to PyQt4 QComboBox:

• pyqt4 组合框中的下拉事件/回调

我还发现了另一个包含 QComboBox 精美图片的链接.第一个元素似乎是一个标签，后跟一个列表:

I also found another link that contains a nice image of a QComboBox. The first element seems to be a label followed by a list:

• 从 QComboBox 弹出菜单中捕捉鼠标按钮按下信号

推荐答案

您可以覆盖 showPopup 方法来实现这一点，无论下拉列表如何打开(即通过鼠标、键盘或快捷方式)，它都可以工作:

You can override the showPopup method to achieve this, which will work no matter how the drop-down list is opened (i.e. via the mouse, keyboard, or shortcuts):

from PyQt5 import QtCore, QtWidgets

class ComboBox(QtWidgets.QComboBox):
    popupAboutToBeShown = QtCore.pyqtSignal()

    def showPopup(self):
        self.popupAboutToBeShown.emit()
        super(ComboBox, self).showPopup()

class Window(QtWidgets.QWidget):
    def __init__(self):
        super(Window, self).__init__()
        self.combo = ComboBox(self)
        self.combo.popupAboutToBeShown.connect(self.populateConbo)
        layout = QtWidgets.QVBoxLayout(self)
        layout.addWidget(self.combo)

    def populateConbo(self):
        if not self.combo.count():
            self.combo.addItems('One Two Three Four'.split())

if __name__ == '__main__':

    import sys
    app = QtWidgets.QApplication(sys.argv)
    window = Window()
    window.show()
    sys.exit(app.exec_())

但是，对于您的特定用例，我认为更好的解决方案可能是设置 QSqlQueryModel 在组合框上，以便自动从数据库更新项目.

However, for your particular use-case, I think a better solution might be to set a QSqlQueryModel on the combo-box, so that the items are updated from the database automatically.

这篇关于QComboBox 点击事件的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！