devicememoryinfo.cs

用P/Invoke显示设备内存信息 P/Invoke with compact framework get the Memory Status and Storage Cards

using System;
using System.Collections.Generic;
using System.Text;
using System.IO;
using System.Runtime.InteropServices;

namespace GetStorageCard
{
    public class DeviceMemoryInfo
    {    

        public static bool HasStorageCardPresent
        {
            get
            {
                return DeviceMemoryInfo.IsStorageCard();
            }
        }
        private static long freeBytesAvailable = 0;

        public static long FreeBytesAvailable
        {
            get
            {
                DeviceMemoryInfo.GetStoreageSize();
                return freeBytesAvailable;
            }

        }
        private static long totalBytes = 0;

        public static long TotalBytes
        {
            get
            {
                DeviceMemoryInfo.GetStoreageSize();
                return totalBytes;
            }

        }
        private static long totalFreeBytes = 0;

        public static long TotalFreeBytes
        {
            get
            {
                DeviceMemoryInfo.GetStoreageSize();
                return totalFreeBytes;
            }
        }
        static string directoryName = string.Empty;

        /// <summary>
        /// Set directory Name before get Memory status,default is windows directory
        /// </summary>
        public static string DirectoryName
        {
            get
            {
                return directoryName;
            }
            set
            {
                directoryName = value;
            }
        }

        [DllImport("coredll")]
        private static extern bool GetDiskFreeSpaceEx(string directoryName, ref long freeBytesAvailable, ref long totalBytes, ref long totalFreeBytes);

        private static void GetStoreageSize()
        {
            DiskFreeSpace result = new DiskFreeSpace();
            if (string.IsNullOrEmpty(directoryName))
            {
                directoryName = @"\Windows";
            }
            if (!GetDiskFreeSpaceEx(directoryName, ref result.FreeBytesAvailable, ref result.TotalBytes, ref result.TotalFreeBytes))
            {
                throw new System.ComponentModel.Win32Exception(Marshal.GetLastWin32Error(), "Error retrieving free disk space");
            }
            else
            {
                freeBytesAvailable = result.FreeBytesAvailable;
                totalBytes = result.TotalBytes;
                totalFreeBytes = result.TotalFreeBytes;
            }
        }
        private struct DiskFreeSpace
        {
            /// <summary>
            /// The total number of free bytes on the disk that are available to the user associated with the calling thread.
            /// </summary>
            public long FreeBytesAvailable;
            /// <summary>
            /// The total number of bytes on the disk that are available to the user associated with the calling thread.
            /// </summary>
            public long TotalBytes;
            /// <summary>
            /// The total number of free bytes on the disk.
            /// </summary>
            public long TotalFreeBytes;
        }

        private static bool IsStorageCard()
        {
            bool hasStorageCard = false;
            DirectoryInfo storeageCard = new DirectoryInfo(@"\");
            foreach (DirectoryInfo directory in storeageCard.GetDirectories())
            {
                if (directory.Attributes == (FileAttributes.Temporary | FileAttributes.Directory))
                {
                    hasStorageCard = true;
                    break;
                }
                else
                {
                    return hasStorageCard = false;
                }
            }

            return hasStorageCard;
        }


    }
}