C#获取指定目录最后写入时间的方法

using System;
using System.IO;
class MainClass {
 static void Main(string[] args) {
  FileInfo file = new FileInfo("c:a.txt");
  // Display directory information.
  DirectoryInfo dir = file.Directory;
  Console.WriteLine("Checking directory: " + dir.Name);
  Console.WriteLine("In directory: " + dir.Name);
  Console.Write("Directory exists: ");
  Console.WriteLine(dir.Exists.ToString());
  if (dir.Exists) {
   Console.Write("Directory last updated: ");
   Console.WriteLine(dir.LastWriteTime.ToString());
  }
  Console.WriteLine();
 }
}