c#如何获取cup，内存，硬盘的利用率？

using   System.Collections.Generic;
using   System.ComponentModel;
using   System.Data;
using   System.Drawing;
using   System.Text;
using   System.Windows.Forms;

using   System.Runtime.InteropServices;
namespace   Windows.Help
{
        public   partial   class   SystemInfo   :   Form
        {
                public   SystemInfo()
                {
                        InITializeComponent();
                }

                [DllImport( "kernel32 ")]
                public   static   extern   void   GetWindowsDirectory(StringBuilder   WinDir,   int   count);
                [DllImport( "kernel32 ")]
                public   static   extern   void   GetSystemDirectory(StringBuilder   SysDir,   int   count);
                [DllImport( "kernel32 ")]
                public   static   extern   void   GetSystemInfo(ref   CPU_INFO   cpuinfo);
                [DllImport( "kernel32 ")]
                public   static   extern   void   GlobalMemoryStatus(ref   MEMORY_INFO   meminfo);
                [DllImport( "kernel32 ")]
                public   static   extern   void   GetSystemTime(ref   SYSTEMTIME_INFO   stinfo);

                //定义CPU的信息结构
                [StructLayout(LayoutKind.Sequential)]
                public   struct   CPU_INFO
                {
                        public   uint   dwOemId;
                        public   uint   dwPageSize;
                        public   uint   lpMinimumApplicationAddress;
                        public   uint   lpMaximumApplicationAddress;
                        public   uint   dwActiveProcessorMask;
                        public   uint   dwNumberOfProcessors;
                        public   uint   dwProcessorType;
                        public   uint   dwAllocationGranularITy;
                        public   uint   dwProcessorLevel;
                        public   uint   dwProcessorRevision;
                }

                //定义内存的信息结构
                [StructLayout(LayoutKind.Sequential)]
                public   struct   MEMORY_INFO
                {
                        public   uint   dwLength;
                        public   uint   dwMemoryLoad;
                        public   uint   dwTotalPhys;
                        public   uint   dwAvailPhys;
                        public   uint   dwTotalPageFile;
                        public   uint   dwAvailPageFile;
                        public   uint   dwTotalVirtual;
                        public   uint   dwAvailVirtual;
                }

                //定义系统时间的信息结构
                [StructLayout(LayoutKind.Sequential)]
                public   struct   SYSTEMTIME_INFO
                {
                        public   ushort   wYear;
                        public   ushort   wMonth;
                        public   ushort   wDayOfWeek;
                        public   ushort   wDay;
                        public   ushort   wHour;
                        public   ushort   wMinute;
                        public   ushort   wSecond;
                        public   ushort   wMilliseconds;
                }

                private   void   button1_Click(object   sender,   EventArgs   e)
                {
                        //调用GetWindowsDirectory和GetSystemDirectory函数分别取得Windows路径和系统路径
                        const   int   nChars   =   128;
                        StringBuilder   Buff   =   new   StringBuilder(nChars);
                        GetWindowsDirectory(Buff,   nChars);
                        WindowsDirectory.Text   =   "Windows路径： "   +   Buff.ToString();
                        GetSystemDirectory(Buff,   nChars);
                        SystemDirectory.Text   =   "   系统路径： "   +   Buff.ToString();

                        //调用GetSystemInfo函数获取CPU的相关信息
                        CPU_INFO   CpuInfo;
                        CpuInfo   =   new   CPU_INFO();
                        GetSystemInfo(ref   CpuInfo);
                        NumberOfProcessors.Text   =   "本计算机中有 "   +   CpuInfo.dwNumberOfProcessors.ToString()   +   "个CPU ";
                        ProcessorType.Text   =   "CPU的类型为 "   +   CpuInfo.dwProcessorType.ToString();
                        ProcessorLevel.Text   =   "CPU等级为 "   +   CpuInfo.dwProcessorLevel.ToString();
                        OemId.Text   =   "CPU的OEM   ID为 "   +   CpuInfo.dwOemId.ToString();
                        PageSize.Text   =   "CPU中的页面大小为 "   +   CpuInfo.dwPageSize.ToString();

                        //调用GlobalMemoryStatus函数获取内存的相关信息
                        MEMORY_INFO   MemInfo;
                        MemInfo   =   new   MEMORY_INFO();
                        GlobalMemoryStatus(ref   MemInfo);
                        MemoryLoad.Text   =   MemInfo.dwMemoryLoad.ToString()   +   "%的内存正在使用 ";
                        TotalPhys.Text   =   "物理内存共有 "   +   MemInfo.dwTotalPhys.ToString()   +   "字节 ";
                        AvailPhys.Text   =   "可使用的物理内存有 "   +   MemInfo.dwAvailPhys.ToString()   +   "字节 ";
                        TotalPageFile.Text   =   "交换文件总大小为 "   +   MemInfo.dwTotalPageFile.ToString()   +   "字节 ";
                        AvailPageFile.Text   =   "尚可交换文件大小为 "   +   MemInfo.dwAvailPageFile.ToString()   +   "字节 ";
                        TotalVirtual.Text   =   "总虚拟内存有 "   +   MemInfo.dwTotalVirtual.ToString()   +   "字节 ";
                        AvailVirtual.Text   =   "未用虚拟内存有 "   +   MemInfo.dwAvailVirtual.ToString()   +   "字节 ";

                        //调用GetSystemTime函数获取系统时间信息
                        SYSTEMTIME_INFO   StInfo;
                        StInfo   =   new   SYSTEMTIME_INFO();
                        GetSystemTime(ref   StInfo);
                        Date.Text   =   StInfo.wYear.ToString()   +   "年 "   +   StInfo.wMonth.ToString()   +   "月 "   +   StInfo.wDay.ToString()   +   "日 ";
                        Time.Text   =   (StInfo.wHour   +   8).ToString()   +   "点 "   +   StInfo.wMinute.ToString()   +   "分 "   +   StInfo.wSecond.ToString()   +   "秒 ";

                }

                private   void   button2_Click(object   sender,   EventArgs   e)
                {
                        this.Close();
                }
        }

}