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

namespace demo.ClassHelper.FileOperate
{
    class FileOpen
    {
        [DllImport("kernel32.dll")]
        private static extern IntPtr _lopen(string lpPathName, int iReadWrite);

        [DllImport("kernel32.dll")]
        private static extern bool CloseHandle(IntPtr hObject);

        public static  int OF_READWRITE = 2;
        public static  int OF_SHARE_DENY_NONE = 0x40;
        public static  IntPtr HFILE_ERROR = new IntPtr(-1);

        //txt文件没有handle;

        public static int VerifyFileIsOpen(string strFileName)
        {
            if (!File.Exists(strFileName))
            {
                return -1;
            }
            IntPtr vHandle = _lopen(strFileName, OF_READWRITE | OF_SHARE_DENY_NONE);
            if (vHandle == HFILE_ERROR)
            {//文件已经打开
                return 1;
            }
            CloseHandle(vHandle);
            //文件未打开，并且可用
            return 0;
        }
    }
}