通过WMI (windows管理工具)查找串口设备

Question

这里的想法是能够找到在运行时连接的USB串口设备，从而不知道它的端口号，并在应用程序中使用它从设备中检索信息。

string comportInfo = string.Empty;

using (var entitySearcher = new ManagementObjectSearcher("root\\CIMV2", "SELECT * FROM Win32_PnPEntity WHERE Caption LIKE '%" + SerialPortToFind + "%'"))
{
    using (var serialPortSearcher = new ManagementObjectSearcher("root\\WMI", "SELECT * FROM MSSerial_PortName"))
    {
        //testBase.SamplerWithCancel is like a for loop with exception control, a time between interations and amount of iterations to be made. It expects a true or false value to determine whether a desired condition is met. Failing to return a true value in the specified iterations throws an exception.
        testBase.SamplerWithCancel(() =>
            {
            var portList = serialPortSearcher.Get().Cast<ManagementBaseObject>().ToList();
            var matchingEntities = entitySearcher.Get().Cast<ManagementBaseObject>().First();

            if (portList.Count != 0 && matchingEntities != null)
            {
                foreach (ManagementBaseObject port in portList)
                {
                    if (port["InstanceName"].ToString().Contains(matchingEntities["DeviceID"].ToString()))
                    {
                        comportInfo = port["PortName"].ToString();
                    }
                }
                return true;
            }
            else
                return false;
        }, "Serial port not found", 3, 1500, 500, false, false);
    }
}

代码运行良好，但我想知道在哪里可以改进它，使其更有弹性，更不易出错。

我觉得使用LINQ比我所做的要好得多。

Answer 1

代码运行良好，但我想知道在哪里可以改进它，使其更有弹性，更不易出错。

• 一个非常好的开端是始终使用大括号{}，尽管它们可能是可选的。
• 通过堆叠using块，您可以节省一些水平间距。
• 通过恢复if (portList.Count != 0 && matchingEntities != null)的条件，您可以提前返回，else将是冗余的，并且可以删除，这也节省了一些间距。
• 变量的命名也需要一些改进，例如复数matchingEntities与调用First()的结果不匹配。
• 将matchingEntities["DeviceID"].ToString()的结果存储到变量中将加快速度。

实施上述各点将导致

string comportInfo = string.Empty;

using (var entitySearcher = new ManagementObjectSearcher("root\\CIMV2", "SELECT * FROM Win32_PnPEntity WHERE Caption LIKE '%" + SerialPortToFind + "%'"))    
using (var serialPortSearcher = new ManagementObjectSearcher("root\\WMI", "SELECT * FROM MSSerial_PortName"))
{
    //testBase.SamplerWithCancel is like a for loop with exception control, a time between interations and amount of iterations to be made. It expects a true or false value to determine whether a desired condition is met. Failing to return a true value in the specified iterations throws an exception.
    testBase.SamplerWithCancel(() =>
        {
        var portList = serialPortSearcher.Get().Cast<ManagementBaseObject>().ToList();
        var matchingEntity = entitySearcher.Get().Cast<ManagementBaseObject>().First();

        if (portList.Count == 0 || matchingEntity == null)
        {
            return false;
        }

        string entity = matchingEntity["DeviceID"].ToString();

        foreach (ManagementBaseObject port in portList)
        {
            if (port["InstanceName"].ToString().Contains(entity))
            {
                comportInfo = port["PortName"].ToString();
            }
        }

        return true;

    }, "Serial port not found", 3, 1500, 500, false, false);
}

Answer 2

我使用LINQ而不是foreach循环开发了一个迭代，同时还实现了Heslacher建议的改进，代码现在如下所示：

string comportInfo = string.Empty;

using (var entitySearcher = new ManagementObjectSearcher("root\\CIMV2", "SELECT * FROM Win32_PnPEntity WHERE Caption LIKE '%" + SerialPortToFind + "%'"))
using (var serialPortSearcher = new ManagementObjectSearcher("root\\WMI", "SELECT * FROM MSSerial_PortName"))
{
    testBase.SamplerWithCancel(() =>
        {
            var portList = serialPortSearcher.Get().Cast<ManagementBaseObject>().ToList();
            var matchingEntity = entitySearcher.Get().Cast<ManagementBaseObject>().First();

            if (portList.Count == 0 || matchingEntity == null)
            {
                return false;
            }

            var entity = matchingEntity["DeviceID"].ToString();

            comportInfo = portList.Select(x => x)
                .Where<ManagementBaseObject>(x => x["InstanceName"].ToString().Contains(entity))
                .First()["PortName"].ToString();

            return true;
        }, "Device not found", 3, 1500, 500, false, false);
}