通过交叉检查在两个文件夹中查找新文件

Question

I am trying to sort two folders in to a patched folder, finding which file is new in the new folder and marking it as new, so i can transfer that file only. i dont care about dates or hash changes. just what file is in the new folder that is not in the old folder.

somehow the line

pf.NFile = !( oldPatch.FindAll(s => s.Equals(f)).Count() == 0);

is always returning false. is there something wrong with my logic of cross checking?

List<string> newPatch = DirectorySearch(_newFolder);
List<string> oldPatch = DirectorySearch(_oldFolder);

foreach (string f in newPatch)
{
    string filename = Path.GetFileName(f);
    string Dir = (Path.GetDirectoryName(f).Replace(_newFolder, "") + @"\");
    PatchFile pf = new PatchFile();
    pf.Dir = Dir;
    pf.FName = filename;
    pf.NFile = !( oldPatch.FindAll(s => s.Equals(f)).Count() == 0);
    nPatch.Files.Add(pf);
 }

foreach (string f in oldPatch)
{
    string filename = Path.GetFileName(f);
    string Dir = (Path.GetDirectoryName(f).Replace(_oldFolder, "") + @"\");
    PatchFile pf = new PatchFile();
    pf.Dir = Dir;
    pf.FName = filename;

    if (!nPatch.Files.Exists(item => item.Dir == pf.Dir && 
                             item.FName == pf.FName))
    {
        nPatch.removeFiles.Add(pf);
    }
}

Answer 1

I don't have the classes you are using (like DirectorySearch and PatchFile ), so i can't compile your code, but IMO the line _oldPatch.FindAll(... doesn't return anything because you are comparing the full path ( c:\\oldpatch\\filea.txt is not c:\\newpatch\\filea.txt ) and not the file name only. IMO your algorithm could be simplified, something like this pseudocode (using List.Contains instead of List.FindAll ):

var _newFolder = "d:\\temp\\xml\\b";
var _oldFolder = "d:\\temp\\xml\\a";
List<FileInfo> missing = new List<FileInfo>();
List<FileInfo> nPatch = new List<FileInfo>();
List<FileInfo> newPatch = new DirectoryInfo(_newFolder).GetFiles().ToList();
List<FileInfo> oldPatch = new DirectoryInfo(_oldFolder).GetFiles().ToList();
// take all files in new patch
foreach (var f in newPatch)
{
    nPatch.Add(f);
}
// search for hits in old patch
foreach (var f in oldPatch)
{
    if (!nPatch.Select (p => p.Name.ToLower()).Contains(f.Name.ToLower()))
    {
        missing.Add(f);
    }
}
// new files are in missing

One possible solution with less code would be to select the file names, put them into a list an use the predefined List.Except or if needed List.Intersect methods. This way a solution to which file is in A but not in B could be solved fast like this:

var locationA = "d:\\temp\\xml\\a";
var locationB = "d:\\temp\\xml\\b";
// takes file names from A and B and put them into lists
var filesInA = new DirectoryInfo(locationA).GetFiles().Select (n => n.Name).ToList();
var filesInB = new DirectoryInfo(locationB).GetFiles().Select (n => n.Name).ToList();
// Except retrieves all files that are in A but not in B
foreach (var file in filesInA.Except(filesInB).ToList())
{
    Console.WriteLine(file);
}

I have 1.xml, 2.xml, 3.xml in A and 1.xml, 3.xml in B . The output is 2.xml - missing in B .