比较两个文件夹的内容

使用LINQ比较两个文件夹内容（长度和文件名）

 1 static void CompareTwoFolders()
 2         {
 3             // Create two identical or different temporary folders 
 4             // on a local drive and change these file paths.
 5             string pathA = @"C:\TestDir";
 6             string pathB = @"C:\TestDir2";
 7 
 8             System.IO.DirectoryInfo dir1 = new System.IO.DirectoryInfo(pathA);
 9             System.IO.DirectoryInfo dir2 = new System.IO.DirectoryInfo(pathB);
10 
11             // Take a snapshot of the file system.
12             IEnumerable<System.IO.FileInfo> list1 = dir1.GetFiles("*.*", System.IO.SearchOption.AllDirectories);
13             IEnumerable<System.IO.FileInfo> list2 = dir2.GetFiles("*.*", System.IO.SearchOption.AllDirectories);
14 
15             //A custom file comparer defined below
16             FileCompare myFileCompare = new FileCompare();
17 
18             bool areIdentical = list1.SequenceEqual(list2, myFileCompare);
19 
20             if (areIdentical == true)
21             {
22                 Console.WriteLine("the two folders are the same");
23             }
24             else
25             {
26                 Console.WriteLine("The two folders are not the same");
27             }
28 
29             // Find the common files. It produces a sequence and doesn't 
30             // execute until the foreach statement.
31             var queryCommonFiles = list1.Intersect(list2, myFileCompare);
32 
33             if (queryCommonFiles.Count() > 0)
34             {
35                 Console.WriteLine("The following files are in both folders:");
36                 foreach (var v in queryCommonFiles)
37                 {
38                     Console.WriteLine(v.FullName); //shows which items end up in result list
39                 }
40             }
41             else
42             {
43                 Console.WriteLine("There are no common files in the two folders.");
44             }
45 
46             // Find the set difference between the two folders.
47             // For this example we only check one way.
48             var queryList1Only = (from file in list1
49                                   select file).Except(list2, myFileCompare);
50 
51             Console.WriteLine("The following files are in list1 but not list2:");
52             foreach (var v in queryList1Only)
53             {
54                 Console.WriteLine(v.FullName);
55             }
56 
57         }
58 
59         class FileCompare : System.Collections.Generic.IEqualityComparer<System.IO.FileInfo>
60         {
61             public FileCompare() { }
62 
63             public bool Equals(System.IO.FileInfo f1, System.IO.FileInfo f2)
64             {
65                 return (f1.FullName == f2.FullName &&
66                         f1.Length == f2.Length);
67             }
68 
69             public int GetHashCode(System.IO.FileInfo fi)
70             {
71                 string s = String.Format("{0}{1}", fi.Name, fi.Length);
72                 return s.GetHashCode();
73             }
74         }