C#对路径的访问被拒绝。。。Client.Download（文件链接，路径）

我的代码有问题： 当我尝试从dropbox下载文件并将其放入漫游文件夹时，出现了一些问题，下面是错误日志：

System.Net.WebException: An exception occurred during a WebClient request. --->              System.UnauthorizedAccessException: Access to the path'C:\Users\Marco\AppData\Roaming\.maycraft' is denied.
   at System.IO.__Error.WinIOError(Int32 errorCode, String maybeFullPath)
   at System.IO.FileStream.Init(String path, FileMode mode, FileAccess access, Int32 rights, Boolean useRights, FileShare share, Int32 bufferSize, FileOptions options, SECURITY_ATTRIBUTES secAttrs, String msgPath, Boolean bFromProxy, Boolean useLongPath, Boolean checkHost)
   at System.IO.FileStream..ctor(String path, FileMode mode, FileAccess access)
   at System.Net.WebClient.DownloadFile(Uri address, String fileName)
   --- End of inner exception stack trace ---
   at System.Net.WebClient.DownloadFile(Uri address, String fileName)
   at System.Net.WebClient.DownloadFile(String address, String fileName)
   at MayCraftLauncher.Program.downloadExist() in c:\Users\Marco\Desktop\MayCraftLauncher\C# SourceCode\MayCraftLauncher\MayCraftLauncher\Program.cs:line 71

很明显，我试图用管理员权限运行Visual Studio，但什么都没有

下面是代码：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Net;
using System.Security.Principal;
using System.IO;
using System.IO.Compression;
using Ionic.Zip;

namespace MayCraftLauncher
{
    class Program
    {
        
        public static System.Threading.Thread existDownloading = new System.Threading.Thread(downloadExist);

        public static string userName = Environment.UserName;
        public static string path = @"C:\Users\" + userName + @"\AppData\Roaming\.maycraft\Exist";
        public static string maypath = @"C:\Users\" + userName + @"\AppData\Roaming\.maycraft";
       
        static void Main(string[] args)
        {
            folderExist();
        }

        static void check1()
        {
            while (!Directory.Exists(maypath))
            {
                System.Threading.Thread.Sleep(5000);
            }
            
                existDownloading.Start();
        }

        static void folderExist()
        {
            if (!Directory.Exists(maypath))
            {
                System.Diagnostics.Process.Start(@"C:\Users\Marco\Desktop\MayCraftLauncher.jar");
                check1();
            }
            else
            {
                fileExist();
            }
        }

        static void fileExist()
        {
            if (File.Exists(path)) //Determina se è la prima volta che l'applicazione viene eseguita
            {
                Console.WriteLine("Exist");
                Console.ReadLine();
            }
            else
            {
                existDownloading.Start();
                Console.WriteLine("Downloading...");
            }
        }

        static void downloadExist()
        {
            WebClient Client = new WebClient();
            DateTime btime = DateTime.Now;
            path = @"C:\Users\" + userName + @"\AppData\Roaming\.maycraft\";
            string publicLinkExist = @"https://dl.dropbox.com/u/35356155/minecraft/download/Exist";
            //string publicLinkMods = @"https://dl.dropbox.com/u/35356155/minecraft/download/mods.7z";
            string publicLinkMods = @"https://dl.dropbox.com/u/35356155/minecraft/download/mcp.7z";
            try
            {
                //----------------File downloading-------------------
                Client.DownloadFile(publicLinkExist, path);
                DirectoryInfo dev = Directory.CreateDirectory(path);
                string devpath = @"C:\Users\" + userName + @"\AppData\Roaming\.maycraft";
                Client.DownloadFile(publicLinkMods, devpath);
                DateTime atime = DateTime.Now;
                Console.WriteLine("Downloading time: " + atime.Subtract(btime).TotalSeconds + " sec.");

                //---------------Files Extracion-------------------
                using (ZipFile zip = ZipFile.Read(devpath))
                {
                    zip.ExtractAll(path);
                }
            }
            catch (Exception e)
            {
                Console.WriteLine(e);
                System.IO.File.WriteAllText(@"C:\Users\Marco\Desktop\log.txt", e.ToString());
                Console.ReadKey();
            }
            existDownloading.Abort();
        }


    }
}

---

它正在输出到

\Roaming.maycraft

，它不在

Roaming

文件夹中，而是在

AppData

根目录中，

\Roaming.maycraft

将是一个文件。底线是，这与您没有写入权限的任何地方相同。正如Grant所说，您应该创建一个文件夹，在该文件夹中您可以授予ASP_NET进程权限，并从那里的DropBox下载文件。或者，如果您不需要下载和保存文件，只需要动态地使用内容，则可以使用Path.GetTempFileName获取随机生成的文件的路径，并使用StreamWriter将dropbox文件的内容写入该文件。