<pre> 
static void Main(string[] args)
        {
            List<string> listView1 = new List<string>();
            DirectoryInfo Dir = new DirectoryInfo(System.IO.Path.GetTempPath());

            FileInfo[] Files = Dir.GetFiles();
            int faildelcount = 0;

            foreach (FileInfo file in Files)
            {
                try
                {
                    File.Delete(file.Name);
                }
                catch (Exception ex)
                {
                    faildelcount++;
                }
            }

            Console.WriteLine("Temp files cleared successfully");
            if(faildelcount > 0)
            Console.WriteLine("Unable to delete {0} files", faildelcount.ToString());
            Console.ReadLine();
            
        }

尝试：

File.Delete(file.Name);

string tempfolder = ("C:\\Users\\Administrator\\AppData\\Local\\Temp");
          string[] tempfiles = Directory.GetFiles(tempfolder, "*.*", SearchOption.AllDirectories);


          foreach (string filePath in Directory.GetFiles(tempfolder, "*.*", SearchOption.AllDirectories))
          {
              try
              {
                  FileInfo currentFile = new FileInfo(filePath);
                  currentFile.Delete();

              }
              catch (Exception ex)
              {
                  Debug.WriteLine("Error on file: {0}\r\n   {1}", filePath, ex.Message);
              }

          }