Python调用CANoe时出现COM错误的解决方法咨询

问题描述 #

编写了一个用于打开CANoe并启动测量的Python脚本，已成功启动CANoe，但在调用App.Open加载配置文件时触发com_error，错误信息如下：

Exception has occurred: com_error
(-2147352567, 'Exception occurred.', (0, None, None, None, 0, -2147467259), None)
  File "C:\Users\randomuser\AppData\Local\Temp\gen_py\3.8\7F31DEB0-5BCC-11D3-8562-00105A3E017Bx0x1x55.py", line 538, in Open
    return self._oleobj_.InvokeTypes(7, LCID, 1, (24, 0), ((8, 1), (11, 17), (11, 17)),config
  File "C:\SMP\S_T\Py\ST.py", line 36, in Load
    self.App.Open(cfg)
  File "C:\SMP\S_T\Py\ST.py", line 141, in <module>
    app.Load('CANoeConfig\PythonBasicEmpty.cfg')

已尝试删除自动生成的gen_py文件，但问题仍未解决，代码如下：

import time, os, msvcrt
from win32com.client import *
from win32com.client.connect import *
def DoEvents():
    pythoncom.PumpWaitingMessages()
    time.sleep(.1)
def DoEventsUntil(cond):
    while not cond():
        DoEvents()
class CanoeSync(object):
    """Wrapper class for CANoe Application object"""
    Started = False
    Stopped = False
    ConfigPath = ""
    def __init__(self):
        app = DispatchEx('CANoe.Application')    
        app.Configuration.Modified = False
        ver = app.Version
        print('Loaded CANoe version ', 
            ver.major, '.', 
            ver.minor, '.', 
            ver.Build, '...', sep='')
        self.App = app
        self.Measurement = app.Measurement  
        self.Running = lambda : self.Measurement.Running
        self.WaitForStart = lambda: DoEventsUntil(lambda: CanoeSync.Started)
        self.WaitForStop = lambda: DoEventsUntil(lambda: CanoeSync.Stopped)
        WithEvents(self.App.Measurement, CanoeMeasurementEvents)
    def Load(self, cfgPath):
        # current dir must point to the script file
        cfg = os.path.join(os.curdir, cfgPath)
        cfg = os.path.abspath(cfg)
        print('Opening: ', cfg)
        self.ConfigPath = os.path.dirname(cfg)
        self.Configuration = self.App.Configuration
        self.App.Open(cfg)
    def LoadTestSetup(self, testsetup):
        self.TestSetup = self.App.Configuration.TestSetup
        path = os.path.join(self.ConfigPath, testsetup)
        testenv = self.TestSetup.TestEnvironments.Add(path)
        testenv = CastTo(testenv, "ITestEnvironment2")
         # TestModules property to access the test modules
        self.TestModules = []
        self.TraverseTestItem(testenv, lambda tm: self.TestModules.append(CanoeTestModule(tm)))
    def LoadTestConfiguration(self, testcfgname, testunits):
        """ Adds a test configuration and initialize it with a list of existing test units """
        tc = self.App.Configuration.TestConfigurations.Add()
        tc.Name = testcfgname
        tus = CastTo(tc.TestUnits, "ITestUnits2")
        for tu in testunits:
            tus.Add(tu)
        # TestConfigs property to access the test configuration
        self.TestConfigs = [CanoeTestConfiguration(tc)]
    def Start(self): 
        if not self.Running():
            self.Measurement.Start()
            self.WaitForStart()
    def Stop(self):
        if self.Running():
            self.Measurement.Stop()
            self.WaitForStop()
    '''   
    def RunTestModules(self):
        """ starts all test modules and waits for all of them to finish"""
        # start all test modules
        for tm in self.TestModules:
            tm.Start()
        # wait for test modules to stop
        while not all([not tm.Enabled or tm.IsDone() for tm in app.TestModules]):
            DoEvents()'''
    def RunTestConfigs(self):
        """ starts all test configurations and waits for all of them to finish"""
        # start all test configurations
        for tc in self.TestConfigs:
            tc.Start()
        # wait for test modules to stop
        while not all([not tc.Enabled or tc.IsDone() for tc in app.TestConfigs]):
            DoEvents()
    def TraverseTestItem(self, parent, testf):
        for test in parent.TestModules: 
            testf(test)
        for folder in parent.Folders: 
            found = self.TraverseTestItem(folder, testf)
class CanoeMeasurementEvents(object):
    """Handler for CANoe measurement events"""
    def OnStart(self): 
        CanoeSync.Started = True
        CanoeSync.Stopped = False
        print("< measurement started >")
    def OnStop(self) : 
        CanoeSync.Started = False
        CanoeSync.Stopped = True
        print("< measurement stopped >")
class CanoeTestModule:
    """Wrapper class for CANoe TestModule object"""
    def __init__(self, tm):
        self.tm = tm
        self.Events = DispatchWithEvents(tm, CanoeTestEvents)
        self.Name = tm.Name
        self.IsDone = lambda: self.Events.stopped
        self.Enabled = tm.Enabled
    def Start(self):
        if self.tm.Enabled:
            self.tm.Start()
            self.Events.WaitForStart()
class CanoeTestConfiguration:
    """Wrapper class for a CANoe Test Configuration object"""
    def __init__(self, tc):        
        self.tc = tc
        self.Name = tc.Name
        self.Events = DispatchWithEvents(tc, CanoeTestEvents)
        self.IsDone = lambda: self.Events.stopped
        self.Enabled = tc.Enabled
    def Start(self):
        if self.tc.Enabled:
            self.tc.Start()
            self.Events.WaitForStart()
class CanoeTestEvents:
    """Utility class to handle the test events"""
    def __init__(self):
        self.started = False
        self.stopped = False
        self.WaitForStart = lambda: DoEventsUntil(lambda: self.started)
        self.WaitForStop = lambda: DoEventsUntil(lambda: self.stopped)
    def OnStart(self):
        self.started = True
        self.stopped = False        
        print("<", self.Name, " started >")
    def OnStop(self, reason):
        self.started = False
        self.stopped = True 
        print("<", self.Name, " stopped >")
# -----------------------------------------------------------------------------
# main
# -----------------------------------------------------------------------------
app = CanoeSync()
# loads the sample configuration
app.Load('CANoeConfig\PythonBasicEmpty.cfg')
# add test modules to the configuration
#app.LoadTestSetup('TestEnvironments\Test Environment.tse')
# add a test configuration and a list of test units
app.LoadTestConfiguration('TestConfiguration', ['C:\SMP\S_T\repo\ST\example.vtuexe']) 
# start the measurement
app.Start()    
# runs the test modules
app.RunTestModules()
# runs the test configurations
app.RunTestConfigs()
# wait for a keypress to end the program
print("Press any key to exit ...")
while not msvcrt.kbhit():
    DoEvents()
# stops the measurement
app.Stop()

请问该如何修复这个问题？

解决方法 #

1. 修复路径转义问题 #

Python中反斜杠是转义字符，直接写'CANoeConfig\PythonBasicEmpty.cfg'会导致路径解析错误，改成以下两种方式之一：

• 使用原始字符串：r'CANoeConfig\PythonBasicEmpty.cfg'
• 使用正斜杠：'CANoeConfig/PythonBasicEmpty.cfg'
  同样，LoadTestConfiguration中的路径'C:\SMP\S_T\repo\ST\example.vtuexe'也要做相同修改。

2. 验证配置文件路径有效性 #

检查Load方法中打印的cfg路径，确认该路径下的.cfg文件确实存在，文件名、文件夹名没有拼写错误（注意大小写）。

3. 调整Configuration.Modified的设置时机 #

在CanoeSync的__init__方法中，刚启动CANoe就设置app.Configuration.Modified = False会引发问题——此时未加载任何配置，该属性处于未初始化状态。把这行代码移到Load方法中，加载完配置后再设置：

def Load(self, cfgPath):
    cfg = os.path.join(os.curdir, cfgPath)
    cfg = os.path.abspath(cfg)
    print('Opening: ', cfg)
    self.App.Open(cfg)  # 先加载配置
    self.Configuration = self.App.Configuration
    self.Configuration.Modified = False  # 加载完成后再设置
    self.ConfigPath = os.path.dirname(cfg)

4. 以管理员身份运行脚本 #

CANoe加载配置时可能需要系统权限，右键点击Python脚本或运行脚本的IDE，选择“以管理员身份运行”。

5. 检查CANoe版本与COM接口兼容性 #

如果安装的CANoe版本较新，尝试用EnsureDispatch代替DispatchEx初始化CANoe对象，确保COM接口版本匹配：

app = EnsureDispatch('CANoe.Application')

也可以删除gen_py文件夹后重启脚本，让系统重新生成适配当前CANoe版本的COM封装文件。

6. 关闭后台CANoe进程 #

任务管理器中结束所有CANoe相关进程，避免多个实例冲突导致配置加载失败。

内容的提问来源于stack exchange，提问作者user23057750