原文地址：https://www.cnblogs.com/top5/archive/2010/04/12/1710141.html

/*
需要添加以下命名空間：
using System.IO;
using System.Security.AccessControl;
*/

string sPath = Server.MapPath(文件夾名稱字符串);
Directory.CreateDirectory(sPath);
addpathPower(sPath, "ASPNET", "FullControl");

//////////////////////////////////////////////////

public void addpathPower(string pathname, string username, string power)

{

DirectoryInfo dirinfo = new DirectoryInfo(pathname);

if ((dirinfo.Attributes & FileAttributes.ReadOnly) != 0)
{
dirinfo.Attributes = FileAttributes.Normal;
}

//取得訪問控制列表
DirectorySecurity dirsecurity = dirinfo.GetAccessControl();

switch (power)

{
case "FullControl":
dirsecurity.AddAccessRule(new FileSystemAccessRule(username, FileSystemRights.FullControl, InheritanceFlags.ContainerInherit, PropagationFlags.InheritOnly, AccessControlType.Allow));
break;
case "ReadOnly":
dirsecurity.AddAccessRule(new FileSystemAccessRule(username, FileSystemRights.Read, AccessControlType.Allow));

break;
case "Write":
dirsecurity.AddAccessRule(new FileSystemAccessRule(username, FileSystemRights.Write, AccessControlType.Allow));
break;
case "Modify":
dirsecurity.AddAccessRule(new FileSystemAccessRule(username, FileSystemRights.Modify, AccessControlType.Allow));
break;
}
dirinfo.SetAccessControl(dirsecurity);
}

C#創建文件夾並設置權限