在WM6上查找存储卡路径

当存在存储卡和蓝牙ftp连接时,是否有一种简单的方法可以在Windows Mobile设备上找到存储卡的路径？

安装点通常是"\存储卡",但可以本地化为其他语言或由OEM修改(某些设备使用"\ SD卡"或其他安装点,某些设备支持安装多个存储介质).枚举可用卡的最佳方法是使用FindFirstFlashCard和FindNextFlashCard.

这两个函数都填充了WIN32_FIND_DATA结构.最重要的字段是cFileName,它将包含卡的挂载点的路径(例如"\ Storage Card").

请注意,这些功能也会枚举设备的内部存储器.如果您只关心外部卷,请忽略cFileName为空字符串("")的情况.

使用这些函数需要#include 并链接到note_prj.lib.两者都包含在WM 2000及更高版本的Windows Mobile SDK中.

请记住,"\存储卡"是面向英语的.为不同区域制作的设备可以具有不同的名称.我的设备上存储卡路径的名称因我使用设备的方式而异.

前段时间我在MSDN表单中回答了一些关于如何检测文件系统中存储卡的问题,以及如何获得存储卡的容量.我写了以下内容可能是对这些问题的回答,并认为分享会有所帮助.存储卡在文件系统中显示为临时目录.此程序检查设备根目录中的对象,任何具有temp属性的文件夹都被视为肯定匹配

using System;
using System.IO;
using System.Runtime.InteropServices;

namespace StorageCardInfo
{
    class Program
    {
        const ulong Megabyte = 1048576;
        const ulong Gigabyte = 1073741824;

        [DllImport("CoreDLL")]
        static extern int GetDiskFreeSpaceEx(
        string DirectoryName,
        out ulong lpFreeBytesAvailableToCaller,
        out ulong lpTotalNumberOfBytes,
        out ulong lpTotalNumberOfFreeBytes 
    );

    static void Main(string[] args)
    {
        DirectoryInfo root = new DirectoryInfo("\\");
        DirectoryInfo[] directoryList = root.GetDirectories();
        ulong FreeBytesAvailable;
        ulong TotalCapacity;
        ulong TotalFreeBytes;

        for (int i = 0; i < directoryList.Length; ++i)
        {
            if ((directoryList.Attributes & FileAttributes.Temporary) != 0)
            {
                GetDiskFreeSpaceEx(directoryList.FullName, out FreeBytesAvailable, out TotalCapacity, out TotalFreeBytes);
                Console.Out.WriteLine("Storage card name: {0}", directoryList.FullName);
                Console.Out.WriteLine("Available Bytes : {0}", FreeBytesAvailable);
                Console.Out.WriteLine("Total Capacity : {0}", TotalCapacity);
                Console.Out.WriteLine("Total Free Bytes : {0}", TotalFreeBytes);
            }
        }
    }
}

我发现使用FindFirstFlashCard/FindNextFlashCard API比枚举目录和检查临时标志(例如将返回蓝牙共享文件夹)更可靠.

以下示例应用程序演示了如何使用它们以及所需的P/Invoke语句.

using System;
using System.Runtime.InteropServices;

namespace RemovableStorageTest
{
    class Program
    {
        static void Main(string[] args)
        {
            string removableDirectory = GetRemovableStorageDirectory();
            if (removableDirectory != null)
            {
                Console.WriteLine(removableDirectory);
            }
            else
            {
                Console.WriteLine("No removable drive found");
            }
        }

        public static string GetRemovableStorageDirectory()
        {
            string removableStorageDirectory = null;

            WIN32_FIND_DATA findData = new WIN32_FIND_DATA();
            IntPtr handle = IntPtr.Zero;

            handle = FindFirstFlashCard(ref findData);

            if (handle != INVALID_HANDLE_VALUE)
            {
                do
                {
                    if (!string.IsNullOrEmpty(findData.cFileName))
                    {
                        removableStorageDirectory = findData.cFileName;
                        break;
                    }
                }
                while (FindNextFlashCard(handle, ref findData));
                FindClose(handle);
            }

            return removableStorageDirectory;
        }

        public static readonly IntPtr INVALID_HANDLE_VALUE = (IntPtr)(-1);

        // The CharSet must match the CharSet of the corresponding PInvoke signature
        [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Auto)]
        public struct WIN32_FIND_DATA
        {
            public int dwFileAttributes;
            public FILETIME ftCreationTime;
            public FILETIME ftLastAccessTime;
            public FILETIME ftLastWriteTime;
            public int nFileSizeHigh;
            public int nFileSizeLow;
            public int dwOID;
            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 260)]
            public string cFileName;
            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 14)]
            public string cAlternateFileName;
        }

        [StructLayout(LayoutKind.Sequential)]
        public struct FILETIME
        {
            public int dwLowDateTime;
            public int dwHighDateTime;
        };

        [DllImport("note_prj", EntryPoint = "FindFirstFlashCard")]
        public extern static IntPtr FindFirstFlashCard(ref WIN32_FIND_DATA findData);

        [DllImport("note_prj", EntryPoint = "FindNextFlashCard")]
        [return: MarshalAs(UnmanagedType.Bool)]
        public extern static bool FindNextFlashCard(IntPtr hFlashCard, ref WIN32_FIND_DATA findData);

        [DllImport("coredll")]
        public static extern bool FindClose(IntPtr hFindFile);
    }
}