我想在 Python for .NET (pythonnet) 的帮助下使用 DLL。 此 DLL 中的方法需要(指向?)变量作为参数。
我可以弄清楚如何调用方法并提供整数变量作为参数。
如果需要特殊类型,我无法弄清楚如何提供这样的参数变量(此处:FTD2XX_NET.FTDI.FT_DEVICE_INFO_NODE[])。
当尝试调用 FTDI.GetDeviceList
的不同变体(其中一些在技术上是相同的)时,我收到不同类型的错误:
类型错误:没有方法与给定参数匹配
FTDI.GetDeviceList([ftdi.FT_DEVICE_INFO_NODE()][:])
FTDI.GetDeviceList(ftdi.FT_DEVICE_INFO_NODE)
FTDI.GetDeviceList(ftdi.FT_DEVICE_INFO_NODE())
FTDI.GetDeviceList(ftdi.FT_DEVICE_INFO_NODE(device_count))
FTDI.GetDeviceList([devicelist_])
FTDI.GetDeviceList(devicelist_)
类型错误:无法索引的对象
FTDI.GetDeviceList(ftdi.FT_DEVICE_INFO_NODE()[:])
类型错误:预期类型
FTDI.GetDeviceList(ftdi.FT_DEVICE_INFO_NODE[:])
FTDI.GetDeviceList(ftdi.FT_DEVICE_INFO_NODE[1])
FTDI.GetDeviceList(ftdi.FT_DEVICE_INFO_NODE[0])
这里是代码摘要和结果:
import clr
import sys
sys.path.append("C:\\Users\\[...]\\FTD2XX_NET_v1.1.0\\") # path to dll
clr.AddReference("System")
clr.AddReference("FTD2XX_NET")
from FTD2XX_NET import FTDI
from System import UInt32
ftdi = FTDI()
if __name__ == '__main__':
# This method requires an integer as parameter, the code is working
# M:FTD2XX_NET.FTDI.GetLibraryVersion(System.UInt32@)
# summary: Gets the current FTD2XX.DLL driver version number.
# returns: FT_STATUS value from FT_GetLibraryVersion in FTD2XX.DLL
# param: name: LibraryVersion. The current library version.
version_ = 0 # empty variable to provide as parameter
ft_status, version = ftdi.GetLibraryVersion(version_)
print('status: {}\nversion: {}'.format(ft_status, version))
# prints
# status: 0
# version: 197140
# This method requires an FT_DEVICE_INFO_NODE[] as parameter, the code is not working
# M:FTD2XX_NET.FTDI.GetDeviceList(FTD2XX_NET.FTDI.FT_DEVICE_INFO_NODE[])
# summary: Gets information on all of the FTDI devices available.
# returns: FT_STATUS value from FT_GetDeviceInfoDetail in FTD2XX.DLL
# param: name: devicelist.
# An array of type FT_DEVICE_INFO_NODE to contain the device information
# for all available devices.
# no idea how to create the fitting parameter FT_DEVICE_INFO_NODE[]
devicelist_ = ftdi.FT_DEVICE_INFO_NODE() # empty variable to provide as parameter
print(devicelist_.Flags, devicelist_.Type, devicelist_.ID,
devicelist_.LocId, devicelist_.SerialNumber,
devicelist_.Description, devicelist_.ftHandle)
# prints
# 0 0 0 0 None None 0
status, devicelist = FTDI.GetDeviceList(devicelist_)
print(devicelist)
# throws a TypeError: No method matches given arguments
Here我发现一些 C# 代码,其中在方法中使用 FT_DEVICE_INFO_NODE[] 和 GetDeviceList:
private int countDevices()
{
FTDI.FT_STATUS ftStatus = FTDI.FT_STATUS.FT_OK;
ftStatus = myDevice.GetNumberOfDevices(ref ftdiDeviceCount);
if (ftStatus != FTDI.FT_STATUS.FT_OK)
return 0;
if (ftdiDeviceCount > 0)
{
//allocate device info list
ftdiDeviceList = new FTDI.FT_DEVICE_INFO_NODE[ftdiDeviceCount];
//populate list
ftStatus = myDevice.GetDeviceList(ftdiDeviceList);
if (ftStatus == FTDI.FT_STATUS.FT_OK)
{
return (int)ftdiDeviceCount;
}
else
return 0;
}
else
return 0;
}
将 FTDI.FT_DEVICE_INFO_NODE[]
作为参数提供给 FTDI.GetDeviceList
时,我缺少什么?
来自 FTDI 的 USB 驱动程序已在此处下载:http://www.ftdichip.com/Drivers/D2XX.htm ,.Net 包装器是从这里下载的:http://www.ftdichip.com/Support/SoftwareExamples/CodeExamples/CSharp.htm
最佳答案
源代码需要一个包含 FT_DEVICE_INFO_NODE 的列表。这是函数声明:
public FTDI.FT_STATUS GetDeviceList(FTDI.FT_DEVICE_INFO_NODE[] devicelist)
这段代码对我有用:
ft_device_info_node = ftdi.FT_DEVICE_INFO_NODE()
ft_status = ftdi.GetDeviceList([ft_device_info_node])
print(ft_status)
最终我放弃了这个函数,因为我无法让它返回我想要的东西,而是在打开我想要的设备后分别使用“GetDeviceID”,“GetDescription”和“GetSerialNumber”函数获取信息。
示例:
# Open
ftdi.OpenByIndex(0)
print("Opened Index 0")
# Get Device ID
device_id = 0
ft_status, device_id = ftdi.GetDeviceID(device_id)
assert(ft_status == 0)
print(device_id)
# Close
ftdi.Close()
print("Closed")
关于Python for .NET : How to provide a variable of special type (FTDI. FT_DEVICE_INFO_NODE[]) 作为方法参数,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/50254745/