Beginner-friendly method to get list of all files and directories

Question

Using .NET 3.0, I've got the method below which correctly returns a collection of all of the files and directories (and sub-directories) of a specified directory. I'd like to, if possible, dumb this down to only use constructs that I'm pretty comfortable with. Specifically, here are the things I'm not clear on:

1. IEnumerable<FileSystemInfo>: I'd like to return List<FileSystemInfo> instead
2. Stack<FileSystemInfo>: I'd list to use List<FileSystemInfo> instead.
3. yield return: I've never used this before

.

public static IEnumerable<FileSystemInfo> GetAllFilesAndDirectories ( string dir ) {

    DirectoryInfo dirInfo = new DirectoryInfo( dir );
    Stack<FileSystemInfo> stack = new Stack<FileSystemInfo>();

    stack.Push( dirInfo );
    while ( dirInfo != null || stack.Count > 0 ) {
        FileSystemInfo fileSystemInfo = stack.Pop();
        DirectoryInfo subDirectoryInfo = fileSystemInfo as DirectoryInfo;
        if ( subDirectoryInfo != null ) {
            yield return subDirectoryInfo;
            foreach ( FileSystemInfo fsi in subDirectoryInfo.GetFileSystemInfos() ) {
                stack.Push( fsi );
            }
            dirInfo = subDirectoryInfo;
        } else {
            yield return fileSystemInfo;
            dirInfo = null;
        }
    }

}

.

The argument could be made that I should just get comfortable with the code above, but that's not what I'm shooting for today.

Thanks in advance

Answer 1

Here is the shortest way I can think of:

static List<FileSystemInfo> GetAllFilesAndDirectories(string dir)
{
    DirectoryInfo dirInfo = new DirectoryInfo(dir);            
    List<FileSystemInfo> allFilesAndDirectories = new List<FileSystemInfo>();

    allFilesAndDirectories.AddRange(dirInfo.GetFiles("*", SearchOption.AllDirectories));
    allFilesAndDirectories.AddRange(dirInfo.GetDirectories("*", SearchOption.AllDirectories));

    return allFilesAndDirectories;
}

It will return a list of all files and directories at all levels, starting from the given path. The order it returns them in would be all files, then all directories.

Answer 2

I believe you're looking for the existing method GetFileSystemInfos(string, SearchOptions). If you specify AllDirectories as the SearchOptions value it will recursively search the passed in folder.

For Example:

public static List<FileSystemInfo> GetAllFilesAndDirectories ( string dir ) {
  DirectoryInfo info = new DirectoryInfo(dir);
  FileSystemInfo[] all = info.GetFileSystemInfos("*", SearchOptions.AllDirectories);
  return new List<FileSystemInfo>(all);
}

If you want to write it out the long way though you can do the following

public static List<FileSystemInfo> GetAllFilesAndDirectories ( string dir ) {
  int i = 0; 
  List<DirectoryInfo> toProcess = new List<DirectoryInfo>();
  List<FileSystemInfo> list = new List<FileSystemInfo>();
  toProcess.Add(new DirectoryInfo(dir));
  while ( i < toProcess.Count ) { 
    DirectoryInfo curDir = toProcess[i];
    foreach ( FileSystemInfo curFile in curDir.GetFileSystemInfos() ) {
      list.Add(curFile);
      DirectoryInfo maybe = curFile as DirectoryInfo;
      if ( maybe != null ) {
        toProcess.Add(maybe);
      }
    i++;
  }
  return list;
}

  FileSystemInfo[] all = info.GetFileSystemInfos("*", SearchOptions.AllDirectories);
  return new List<FileSystemInfo>(all);
}