在C# .NET Framework应用中如何获取连接PC的SD卡盘符

问题描述 #

我已经查阅了该主题下的相关推荐问题，但均未找到符合需求的解决方案。
目前尝试的方案存在以下问题：

• 使用System.IO.DriveInfo.GetDrives()或者搭配查询语句Win32_LogicalDisk的System.Management.ManagementObjectSearcher()，可以获取所有设备的盘符，但无法区分哪个是SD卡设备
• 使用查询条件为Caption = 'SDHC Card'的CIM_LogicalDevice查询的ManagementObjectSearcher()，可以获取2个Caption属性为SDHC Card的设备，但无法得到对应的盘符信息

补充说明 #

我可以手动从CIM_LogicalDisk查询结果中通过VolumeName属性确认SD卡对应的逻辑盘符，也可以从CIM_LogicalDevice查询结果中通过Name、Caption、Model属性确认SD卡对应的物理设备，但程序无法自动识别二者的对应关系。
需要注意的是，盘符和PHYSICALDRIVE编号的对应关系不是固定的，会随着不同可移动设备的插拔发生变化，需要在代码中实现逻辑盘与物理盘的自动对应关联。

已尝试的代码 #

using System;
using System.Management;

namespace Code3
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine("\tfrom: 'ManagementObjectSearcher()' with query \"Win32_LogicalDisk\"");
            var searcher1 = new ManagementObjectSearcher(@"\root\cimv2", "SELECT * FROM Win32_LogicalDisk");
            foreach (ManagementBaseObject disk in searcher1.Get())
            {
                string diskID = disk.GetPropertyValue("DeviceID").ToString();
                int driveType = Convert.ToInt32(disk.GetPropertyValue("DriveType"));
                string diskCaption = disk.GetPropertyValue("Caption").ToString();
                string diskDescription = disk.GetPropertyValue("Description").ToString();
                string diskName = disk.GetPropertyValue("Name").ToString();
                int diskMediaType = Convert.ToInt32(disk.GetPropertyValue("MediaType"));
                Console.WriteLine($"{diskName} - ID: {diskID},  Caption: {diskCaption},  Desc.: {diskDescription,-16},  Drive Type: {driveType},  Media Type: {diskMediaType}.");
            }
            Console.WriteLine();

            Console.WriteLine("\tfrom: 'ManagementObjectSearcher()' with query SelectQuery(\"CIM_LogicalDevice\", \"Caption = 'SDHC Card'\")");
            ManagementScope mgmtScope = new ManagementScope(@"\root\cimv2");
            SelectQuery devQuery = new SelectQuery("CIM_LogicalDevice", "Caption = 'SDHC Card'");
            var searcher2 = new ManagementObjectSearcher(mgmtScope, devQuery);

            foreach (ManagementBaseObject device in searcher2.Get())
            {
                Console.WriteLine($"{device.GetPropertyValue("Name"),-15} - Caption: {device.GetPropertyValue("Caption")},  Device ID: {device.GetPropertyValue("DeviceID")}.");
                continue; // ... to skip property display

                if (!string.IsNullOrEmpty(device.GetPropertyValue("Name").ToString()))
                {
                    PropertyDataCollection props = device.Properties;
                    Console.WriteLine($"\n\t\tProperties of {device.GetPropertyValue("DeviceID")} Drive: \n");
                    foreach (var prop in device.Properties)
                    {
                        if (prop.Value != null)
                            Console.WriteLine($"{prop.Name,-20} - {prop.Type,-8} - {prop.Value ?? "(null)"}");
                    }
                    Console.WriteLine();
                }
            }

            Console.ReadKey();
        }
    }
}

解决方案 #

通过WMI的关联类串联物理磁盘、磁盘分区、逻辑盘符三层关系，结合SD卡的设备特征筛选即可实现需求，完整实现代码如下：

using System;
using System.Collections.Generic;
using System.Management;

namespace SdCardDetector
{
    class Program
    {
        static void Main(string[] args)
        {
            List<string> sdCardDrives = GetSdCardDriveLetters();
            Console.WriteLine("检测到的SD卡盘符：");
            foreach (string drive in sdCardDrives)
            {
                Console.WriteLine(drive);
            }
            Console.ReadKey();
        }

        static List<string> GetSdCardDriveLetters()
        {
            List<string> result = new List<string>();
            // 筛选SD卡物理磁盘，可根据自己设备的属性调整关键词
            string[] sdKeywords = { "SD", "SDHC", "SDXC", "Secure Digital", "读卡器", "Card Reader" };
            
            // 第一步：遍历所有物理磁盘
            using (var diskSearcher = new ManagementObjectSearcher(@"root\cimv2", "SELECT * FROM Win32_DiskDrive"))
            {
                foreach (ManagementObject disk in diskSearcher.Get())
                {
                    string caption = disk["Caption"]?.ToString() ?? "";
                    string model = disk["Model"]?.ToString() ?? "";
                    bool isSdDisk = false;
                    foreach (string keyword in sdKeywords)
                    {
                        if (caption.IndexOf(keyword, StringComparison.OrdinalIgnoreCase) >= 0 
                            || model.IndexOf(keyword, StringComparison.OrdinalIgnoreCase) >= 0)
                        {
                            isSdDisk = true;
                            break;
                        }
                    }
                    if (!isSdDisk) continue;

                    // 第二步：关联查询该物理磁盘对应的分区
                    string partitionQuery = $"ASSOCIATORS OF {{Win32_DiskDrive.DeviceID='{disk["DeviceID"]?.ToString().Replace("\\", "\\\\")}'}} WHERE AssocClass=Win32_DiskDriveToDiskPartition";
                    using (var partitionSearcher = new ManagementObjectSearcher(partitionQuery))
                    {
                        foreach (ManagementObject partition in partitionSearcher.Get())
                        {
                            // 第三步：关联查询分区对应的逻辑盘符
                            string logicalDiskQuery = $"ASSOCIATORS OF {{Win32_DiskPartition.DeviceID='{partition["DeviceID"]}'}} WHERE AssocClass=Win32_LogicalDiskToPartition";
                            using (var logicalSearcher = new ManagementObjectSearcher(logicalDiskQuery))
                            {
                                foreach (ManagementObject logicalDisk in logicalSearcher.Get())
                                {
                                    string driveLetter = logicalDisk["DeviceID"]?.ToString();
                                    if (!string.IsNullOrEmpty(driveLetter) && !result.Contains(driveLetter))
                                    {
                                        result.Add(driveLetter);
                                    }
                                }
                            }
                        }
                    }
                }
            }
            return result;
        }
    }
}

注意事项 #

• 使用前需要在项目引用中添加System.Management程序集
• 如果设备识别不准确，可以打印所有Win32_DiskDrive的Caption和Model属性，调整筛选关键词即可
• 支持多读卡器/多SD卡同时接入的场景，会返回所有符合条件的盘符

内容的提问来源于stack exchange，提问作者JNygrenLT