使用多线程执行几秒钟后崩溃[重复]

Question

基于here 和here 的代码，我在PyQt5 中迈出了多线程的第一步。启动程序后，出现图形用户界面，但几秒钟后它崩溃并出现以下错误

Process finished with exit code -1073740791 (0xC0000409)

在谷歌搜索错误消息后，我比较确定多线程有问题。不幸的是，我不知道错误是什么以及如何修复。

代码

import sys
from datetime import datetime

import wmi

from PyQt5. QtCore import QObject, QRunnable, QThreadPool, pyqtSignal, pyqtSlot
from PyQt5.QtWidgets import QApplication, QMainWindow, QTableWidget, QTableWidgetItem, QHeaderView


class KeyboardDetectorSignals(QObject):
    keyboard_changed = pyqtSignal(str)


class KeyboardDetector(QRunnable):

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

        self.signals = KeyboardDetectorSignals()

    def run(self):

        device_connected_wql = "SELECT * FROM __InstanceCreationEvent WITHIN 2 WHERE TargetInstance ISA \'Win32_Keyboard\'"
        device_disconnected_wql = "SELECT * FROM __InstanceDeletionEvent WITHIN 2 WHERE TargetInstance ISA \'Win32_Keyboard\'"

        c = wmi.WMI()
        connected_watcher = c.watch_for(raw_wql=device_connected_wql)
        disconnected_watcher = c.watch_for(raw_wql=device_disconnected_wql)

        while True:
            try:
                connected = connected_watcher(timeout_ms=10)
            except wmi.x_wmi_timed_out:
                pass
            else:
                if connected:
                    self.signals.keyboard_changed.emit("Keyboard connected.")

            try:
                disconnected = disconnected_watcher(timeout_ms=10)
            except wmi.x_wmi_timed_out:
                pass
            else:
                if disconnected:
                    self.signals.keyboard_changed.emit("Keyboard disconnected.")


class MainWindow(QMainWindow):

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

        self.setGeometry(100, 100, 500, 500)
        self.setWindowTitle("Keyboard Logger")

        self.log_table = QTableWidget()
        self.log_table.setColumnCount(2)
        self.log_table.setShowGrid(True)
        self.log_table.setHorizontalHeaderLabels(["Time", "Event"])
        self.log_table.horizontalHeader().setStretchLastSection(True)
        self.log_table.horizontalHeader().setSectionResizeMode(QHeaderView.ResizeToContents)
        self.setCentralWidget(self.log_table)
        self.show()

        self.threadpool = QThreadPool()
        keyboard_detector = KeyboardDetector()
        keyboard_detector.signals.keyboard_changed.connect(self.add_row)
        self.threadpool.start(keyboard_detector)

    def add_row(self, event: str):
        now = datetime.now()
        datetime_string = now.strftime("%Y-%m-%d %H:%M:%S")

        row_count = self.log_table.rowCount()
        self.log_table.insertRow(row_count)
        self.log_table.setItem(row_count, 0, QTableWidgetItem(datetime_string))
        self.log_table.setItem(row_count, 1, QTableWidgetItem(event))


def main():
    app = QApplication(sys.argv)
    window = MainWindow()
    sys.exit(app.exec_())


if __name__ == '__main__':
    main()

---

更新 1： 删除了 @pyqtSlot()。

从 CMD 运行脚本时出现以下错误：

Traceback (most recent call last):
  File "c:\users\ata\pycharmprojects\test\src\wmi\wmi.py", line 1340, in connect
    obj = GetObject(moniker)
  File "C:\Users\ata\AppData\Local\Programs\Python\Python37\lib\site-packages\win32com\client\__init__.py", line 72, in GetObject
    return Moniker(Pathname, clsctx)
  File "C:\Users\ata\AppData\Local\Programs\Python\Python37\lib\site-packages\win32com\client\__init__.py", line 87, in Moniker
    moniker, i, bindCtx = pythoncom.MkParseDisplayName(Pathname)
pywintypes.com_error: (-2147221020, 'Ung³ltige Syntax', None, None)

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "c:\users\ata\pycharmprojects\test\src\wmi\wmi.py", line 1354, in connect
    handle_com_error()
  File "c:\users\ata\pycharmprojects\test\src\wmi\wmi.py", line 258, in handle_com_error
    raise klass(com_error=err)
wmi.x_wmi_uninitialised_thread: <x_wmi: Unexpected COM Error (-2147221020, 'Ung³ltige Syntax', None, None)>

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "main.py", line 26, in run
    c = wmi.WMI()
  File "c:\users\ata\pycharmprojects\test\src\wmi\wmi.py", line 1357, in connect
    raise x_wmi_uninitialised_thread("WMI returned a syntax error: you're probably running inside a thread without first calling pythoncom.CoInitialize[Ex]")
wmi.x_wmi_uninitialised_thread: <x_wmi: WMI returned a syntax error: you're probably running inside a thread without first calling pythoncom.CoInitialize[Ex] (no underlying exception)>
PS C:\Users\ata\PycharmProjects\Snippets\KeyboardLogger>

Answer 1

PyQt 是线程安全的，与Qt 是线程安全的程度相同。 Qt docs 会告诉您他们的 API 的哪些部分可以保证如此，以及在什么情况下。

Cross-thread signals 是thread-safe.

编写此代码的线程安全方式是使用mutex