Extracting files and directories from a provided list into separate lists

This code gets a list of all files and directories from a specific location. Thes code below works.

List FullList = new List(LoadFiles("patch.txt"));
List ShortCatalogList = new List();
List ShortFileList = new List();

            for (int i = 0; i  0)
                        {                           
                            string[] subFile = Directory.GetFiles(FullList[i]);
                                for (int io = 0; io  0)
                     {
                            string[] subFolder = Directory.GetDirectories(FullList[i]);

                            for (int io = 0; io < subFolder.Length; io++)
                            {
                                FullList.Add(subFolder[io]);
                            }                   
                   }
                  }
                 }

I know that I need to protect from permission problem.

Most is said about this code in the other answer, but there is a simplification which can be used to beautify this code a lot.

The Directory class has two methods which returns IEnumerable namely EnumerateFiles() and EnumerateDirectories().

The results of the calls to this methods can be used to call AddRange() on the ShortFileList and FullList.

Like so

List fullList = new List(LoadFiles("patch.txt"));
List shortCatalogList = new List();
List shortFileList = new List();

for (int i = 0; i < fullList.Count; i++)
{

    if (System.IO.Path.HasExtension(fullList[i]))
    {
        shortFileList.Add(fullList[i]);
        continue;
    }

    shortCatalogList.Add(fullList[i]);

    var files = Directory.EnumerateFiles(fullList[i]);
    shortFileList.AddRange(files);

    var directories = Directory.EnumerateDirectories(fullList[i]);
    fullList.AddRange(directories);

}

StackExchange Code Review Q#114137, answer score: 5