C# 在控制台做文件拷贝。源文件和目标文件都0 KB了。

Question

using System;
using System.Collections.Generic;
using System.Text;
using System.IO;namespace copy_file1
{
    class Program
    {
        static void Main(string[] args)
        {
            string path = @"c:\temp\MyTest.txt";
            string path2 = path + "temp";            try
            {
                using (FileStream fs = File.Create(path)) { }
                // Ensure that the target does not exist.
                File.Delete(path2);                // Copy the file.
                File.Copy(path, path2);
                Console.WriteLine("{0} copied to {1}", path, path2);                // Try to copy the same file again, which should fail.
                File.Copy(path, path2);
                Console.WriteLine("The second Copy operation succeeded, which was not expected.");
            }            catch (Exception e)
            {
                Console.WriteLine("Double copying is not allowed, as expected.");
                Console.WriteLine(e.ToString());
            }        }
    }
}

Answer 1

这可是 MSDN 里的例子啊。想不明白。等高手。

Answer 2

using System;
using System.Collections.Generic;
using System.Text;
using System.IO;namespace copy_file1
{
    class Program
    {
        static void Main(string[] args)
        {
            string path = @"c:\temp\MyTest.txt";
            string path2 = path + "temp";            try
            {
                //using (FileStream fs = File.Create(path)) { }
                // Ensure that the target does not exist. 
                //File.Delete(path2);                // Copy the file. 
                File.Copy(path, path2);
                Console.WriteLine("{0} copied to {1}", path, path2);                // Try to copy the same file again, which should fail. 
                File.Copy(path, path2);
                Console.WriteLine("The second Copy operation succeeded, which was not expected.");
            }            catch (Exception e)
            {
                Console.WriteLine("Double copying is not allowed, as expected.");
                Console.WriteLine(e.ToString());
            }        }
    }
}

Answer 3

using (FileStream fs = File.Create(path)) { } 
// Ensure that the target does not exist. 
File.Delete(path2); 这里用Create的形式OpenStream，path为源文件，就变为空文件了。

Answer 4

//using (FileStream fs = File.Create(path)) { }
 3楼的办法可以，我也是这样试出来的。但是不知道为什么要注释掉这一行。  
 是重新创建了那个path的文件，是吗？