C# 如何判断 DirectoryInfo.GetFileSystemInfos()返回的是文件还是目录

如下例子，用is判断，
正如下面的 (i is DirectoryInfo)和(i is FileInfo)，i是FileSystemInfo 类型。

// Iterate through each item.
foreach (FileSystemInfo i in FSInfo)
{
// Check to see if this is a DirectoryInfo object.
if (i is DirectoryInfo)
{
// Add one to the directory count.
directories++;

// Cast the object to a DirectoryInfo object.
DirectoryInfo dInfo = (DirectoryInfo)i;

// Iterate through all sub-directories.
ListDirectoriesAndFiles(dInfo.GetFileSystemInfos());
}
// Check to see if this is a FileInfo object.
else if (i is FileInfo)
{
// Add one to the file count.
files++;

}

补充：
DirectoryInfo dir = new DirectoryInfo(directory);
FileSystemInfo[] infos = dir.GetFileSystemInfos();
你能看懂的……

using System;
using System.IO;

class DirectoryFileCount
{

static long files = 0;
static long directories = 0;

static void Main()
{
try
{
Console.WriteLine("Enter the path to a directory:");

string directory = Console.ReadLine();

// Create a new DirectoryInfo object.
DirectoryInfo dir = new DirectoryInfo(directory);

if (!dir.Exists)
{
throw new DirectoryNotFoundException("The directory does not exist.");
}

// Call the GetFileSystemInfos method.
FileSystemInfo[] infos = dir.GetFileSystemInfos();

Console.WriteLine("Working...");

// Pass the result to the ListDirectoriesAndFiles
// method defined below.
ListDirectoriesAndFiles(infos);

// Display the results to the console.
Console.WriteLine("Directories: {0}", directories);
Console.WriteLine("Files: {0}", files);

}
catch (Exception e)
{
Console.WriteLine(e.Message);
}
finally
{

Console.ReadLine();
}
}

static void ListDirectoriesAndFiles(FileSystemInfo[] FSInfo)
{
// Check the FSInfo parameter.
if (FSInfo == null)
{
throw new ArgumentNullException("FSInfo");
}

// Iterate through each item.
foreach (FileSystemInfo i in FSInfo)
{
// Check to see if this is a DirectoryInfo object.
if (i is DirectoryInfo)
{
// Add one to the directory count.
directories++;

// Cast the object to a DirectoryInfo object.
DirectoryInfo dInfo = (DirectoryInfo)i;

// Iterate through all sub-directories.
ListDirectoriesAndFiles(dInfo.GetFileSystemInfos());
}
// Check to see if this is a FileInfo object.
else if (i is FileInfo)
{
// Add one to the file count.
files++;

}

}
}
}

DirectoryInfo di = new DirectoryInfo("");
FileSystemInfo[] infos = di.GetFileSystemInfos();
foreach (FileSystemInfo f in infos)
{
if(Directory.Exists(f.FullName))
{
//目录
}
else if (File.Exists(f.FullName))
{
//文件
}
}