The below code is recursive function that list directories in 2 levels:

static  Dictionary<string,string> pList=new Dictionary<string, string>(); 
static void ListDirec(string path, int start, int end)
    var dirInfo = new DirectoryInfo(path);
    var folders = dirInfo.GetDirectories().ToList();

    foreach (var item in folders)
        Console.WriteLine("".PadLeft(start * 4, ' ') + item.Name);
        if (start < end) {
            ListDirec(item.FullName, start + 1, end);

Now how can optimize that in this case?

For example, I've these directories with their sub-directories:


Now I want save parents as key and children as value in dictionary, with their relation for example folder-A has these children: folder-A-1, folder-A-2, folder-A-3 and so on.

What's the best way to do that in this function?


closed as off-topic by svick, Marc-Andre, syb0rg, p.s.w.g, BenVlodgi Apr 16 '14 at 21:22

This question appears to be off-topic. The users who voted to close gave this specific reason:

  • "Questions containing broken code or asking for advice about code not yet written are off-topic, as the code is not ready for review. Such questions may be suitable for Stack Overflow or Programmers. After the question has been edited to contain working code, we will consider reopening it." – svick, Marc-Andre, syb0rg, p.s.w.g, BenVlodgi
If this question can be reworded to fit the rules in the help center, please edit the question.

  • \$\begingroup\$ You are asking for help in writing code to add the data to a dictionary. This code does not exist yet, so it is not ready for a Code Review. When your code works as designed, bring it back for review. \$\endgroup\$ – rolfl Apr 16 '14 at 21:27

To relate your parent directories to their children, you could have plist declared like this:

static Dictionary<String, List<String>> plist = new Dictionary<string, List<string>>();

Each time you hit a child folder, you add its name to

Console.WriteLine("".PadLeft(start * 4, ' ') + item.Name);
string parent = path.Split('\\').Last();
if (!pList.Keys.Contains(parent))
    pList.Add(parent, new List<string>());

Sorry, I don't have access to a C# compiler at the moment so I can't verify this 100%, but it's a starting point at least.

Edit: After thinking about it, I don't think C# likes it if you use [] before an element is in the Dictionary. I edited the above code to include how to get the parent and included the Console.WriteLine so you know where I would put it.


One option is to use a Dictionary<DirectoryInfo, List<DirectoryInfo>>. This way if you want to access the directories the methods you need are right there:

public static Dictionary<DirectoryInfo, List<DirectoryInfo>> BuildTree(string path)
    Dictionary<DirectoryInfo, List<DirectoryInfo>> temptree = new Dictionary<DirectoryInfo, List<DirectoryInfo>>();
    //If you need to filter the results edit the search string
    foreach(DirectoryInfo dir in new DirectoryInfo(path).GetDirectories("*", SearchOption.TopDirectoryOnly))
        temptree.Add(dir, dir.GetDirectories("*", SearchOption.TopDirectoryOnly).ToList());
    return temptree;

If you would like a LINQ option you could do it this way:

public Dictionary<DirectoryInfo, List<DirectoryInfo>> BuildTree(string path)
    Dictionary<DirectoryInfo, List<DirectoryInfo>> temptree = (from dir in new DirectoryInfo(path).EnumerateDirectories("*", SearchOption.TopDirectoryOnly)
                                                                select dir).ToDictionary(x => x, x => x.GetDirectories("*", SearchOption.TopDirectoryOnly).ToList());
    return temptree;

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