如何检查递归方法是否已经结束？

Question

我刚刚完成了这个递归方法：

/// <summary>
/// Recursively process a given directory and add its file to Library.xml
/// </summary>
/// <param name="sourceDir">Source directory</param>
public void ProcessDir(string sourceDir)
{
    string[] fileEntries = Directory.GetFiles(sourceDir, "*.mp3");
    foreach (string fileName in fileEntries)
    {
        Song newSong = new Song();
        newSong.ArtistName = "test artist";
        newSong.AlbumName = "test album";
        newSong.Name = "test song title";
        newSong.Length = 1234;
        newSong.FileName = fileName;

        songsCollection.Songs.Add(newSong);
    }

    string[] subdirEntries = Directory.GetDirectories(sourceDir);
    foreach (string subdir in subdirEntries)
    {
        if ((File.GetAttributes(subdir) & FileAttributes.ReparsePoint) != FileAttributes.ReparsePoint)
        {
            ProcessDir(subdir);
        }
    }
}

一切都像预期的那样工作，我唯一的问题是:我怎么知道这个方法什么时候完成执行？在.NET中有没有专门为这个目的而设计的东西呢？

Answer 1

在.NET中没有什么特别的东西可以告诉你这一点。基本上，对ProcessDir的第一个调用将在递归结束后返回。

Answer 2

那么，您可以在初始ProcessDir调用之后放置一行代码来指示执行的结束：

ProcessDir("MyDir");
Console.WriteLine("Done!");

Answer 3

您可以尝试使用全局变量来跟踪它。

private int _processDirTrack = 0;

public void ProcessDir(string sourceDir)
{
    _processDirTrack++;  // Increment at the start of each

    string[] fileEntries = Directory.GetFiles(sourceDir, "*.mp3");
    foreach (string fileName in fileEntries)
    {
        Song newSong = new Song();
        newSong.ArtistName = "test artist";
        newSong.AlbumName = "test album";
        newSong.Name = "test song title";
        newSong.Length = 1234;
        newSong.FileName = fileName;

        songsCollection.Songs.Add(newSong);
    }

    string[] subdirEntries = Directory.GetDirectories(sourceDir);
    foreach (string subdir in subdirEntries)
    {
        if ((File.GetAttributes(subdir) & FileAttributes.ReparsePoint) != FileAttributes.ReparsePoint)
        {
            ProcessDir(subdir);
        }
    }

    _processDirTrack--;  // Decrement after the recursion. Fall through means it got to
                         // the end of a branch

    if(_processDirTrack == 0)
    {
        Console.WriteLine("I've finished with all of them.");
    }
}