using System; using System.Collections; using System.IO; namespace ConsoleApplication1 {     /// <summary>     /// 文件排序类     /// </summary>     public class FileSort : IComparer     {         private FileOrder _fileorder;         private FileAsc _fileasc;         /// <summary>         /// 构造函数         /// </summary>         public FileSort()             : this(FileOrder.Name, FileAsc.Asc)         { }         /// <summary>         /// 构造函数         /// </summary>         /// <param name="fileorder"></param>         public FileSort(FileOrder fileorder)             : this(fileorder, FileAsc.Asc)         { }         /// <summary>         /// 构造函数         /// </summary>         /// <param name="fileorder"></param>         /// <param name="fileasc"></param>         public FileSort(FileOrder fileorder, FileAsc fileasc)         {             _fileorder = fileorder;             _fileasc = fileasc;         }         /// <summary>         /// 比较函数         /// </summary>         /// <param name="x"></param>         /// <param name="y"></param>         /// <returns></returns>         public int Compare(object x, object y)         {             FileInfo file1 = x as FileInfo;             FileInfo file2 = y as FileInfo;             FileInfo file3;             if (file1 == null || file2 == null)                 throw new ArgumentException("参数不是FileInfo类实例.");             if (_fileasc == FileAsc.Desc)             {                 file3 = file1;                 file1 = file2;                 file2 = file3;             }             switch (_fileorder)             {                 case FileOrder.Name:                     return file1.Name.CompareTo(file2.Name);                 case FileOrder.Length:                     return file1.Length.CompareTo(file2.Length);                 case FileOrder.Extension:                     return file1.Extension.CompareTo(file2.Extension);                 case FileOrder.CreationTime:                     return file1.CreationTime.CompareTo(file2.CreationTime);                 case FileOrder.LastAccessTime:                     return file1.LastAccessTime.CompareTo(file2.LastAccessTime);                 case FileOrder.LastWriteTime:                     return file1.LastWriteTime.CompareTo(file2.LastWriteTime);                 default:                     return 0;             }         }     }     /// <summary>     /// 排序依据     /// </summary>     public enum FileOrder     {         /// <summary>         /// 文件名         /// </summary>         Name,         /// <summary>         /// 大小         /// </summary>         Length,         /// <summary>         /// 类型         /// </summary>         Extension,         /// <summary>         /// 创建时间         /// </summary>         CreationTime,         /// <summary>         /// 访问时间         /// </summary>         LastAccessTime,         /// <summary>         /// 修改时间         /// </summary>         LastWriteTime     }     /// <summary>     /// 升序降序     /// </summary>     public enum FileAsc     {         /// <summary>         /// 升序         /// </summary>         Asc,         /// <summary>         /// 降序         /// </summary>         Desc     } }