C#设置文件权限

   在开发中，我们经常会使用IO操作，例如创建，删除文件等操作。在项目中这样的需求也较多，我们也会经常对这些操作进行编码，但是对文件的权限进行设置，这样的操作可能会手动操作，现在介绍一种采用代码动态对文件设置权限的操作。

   在对文件进行权限设置在DOtNet中，会采用FileSystemAccessRule类进行文件的权限操作。

    1.现在看一下FileSystemAccessRule的实现代码：

  public FileSystemAccessRule(
            IdentityReference identity,
            FileSystemRights fileSystemRights,
            AccessControlType type )
            : this(
                identity,
                AccessMaskFromRights( fileSystemRights, type ),
                false,
                InheritanceFlags.None,
                PropagationFlags.None,
                type )
        {
        }

        public FileSystemAccessRule(
            String identity,
            FileSystemRights fileSystemRights,
            AccessControlType type )
            : this(
                new NTAccount(identity),
                AccessMaskFromRights( fileSystemRights, type ),
                false,
                InheritanceFlags.None,
                PropagationFlags.None,
                type )
        {
        }

        //
        // Constructor for creating access rules for folder objects
        //

        public FileSystemAccessRule(
            IdentityReference identity,
            FileSystemRights fileSystemRights,
            InheritanceFlags inheritanceFlags,
            PropagationFlags propagationFlags,
            AccessControlType type )
            : this(
                identity,
                AccessMaskFromRights( fileSystemRights, type ),
                false,
                inheritanceFlags,
                propagationFlags,
                type )
        {
        }

        public FileSystemAccessRule(
            String identity,
            FileSystemRights fileSystemRights,
            InheritanceFlags inheritanceFlags,
            PropagationFlags propagationFlags,
            AccessControlType type )
            : this(
                new NTAccount(identity),
                AccessMaskFromRights( fileSystemRights, type ),
                false,
                inheritanceFlags,
                propagationFlags,
                type )
        {
        }
        internal FileSystemAccessRule(
            IdentityReference identity,
            int accessMask,
            bool isInherited,
            InheritanceFlags inheritanceFlags,
            PropagationFlags propagationFlags,
            AccessControlType type )
            : base(
                identity,
                accessMask,
                isInherited,
                inheritanceFlags,
                propagationFlags,
                type )
        {
        }

        #endregion

        #region Public properties

        public FileSystemRights FileSystemRights
        {
            get { return RightsFromAccessMask( base.AccessMask ); }
        }

 
        internal static int AccessMaskFromRights( FileSystemRights fileSystemRights, AccessControlType controlType )
        {
            if (fileSystemRights < (FileSystemRights) 0 || fileSystemRights > FileSystemRights.FullControl)
                throw new ArgumentOutOfRangeException("fileSystemRights", Environment.GetResourceString("Argument_InvalidEnumValue", fileSystemRights, "FileSystemRights"));
            Contract.EndContractBlock();

            if (controlType == AccessControlType.Allow) {
                fileSystemRights |= FileSystemRights.Synchronize;
            }
            else if (controlType == AccessControlType.Deny) {
                if (fileSystemRights != FileSystemRights.FullControl &&
                    fileSystemRights != (FileSystemRights.FullControl & ~FileSystemRights.DeleteSubdirectoriesAndFiles))
                    fileSystemRights &= ~FileSystemRights.Synchronize;
            }

            return ( int )fileSystemRights;
        }

        internal static FileSystemRights RightsFromAccessMask( int accessMask )
        {
            return ( FileSystemRights )accessMask;
        }

    }

     2.由于FileSystemAccessRule继承自AccessRule，现在看一下AccessRule的源码：

/// <summary>
  /// 表示用户的标识、访问掩码和访问控制类型（允许或拒绝）的组合。<see cref="T:System.Security.AccessControl.AccessRule"/> 对象还包含有关子对象如何继承规则以及如何传播继承的信息。
  /// </summary>
  public abstract class AccessRule : AuthorizationRule
  {
    /// <summary>
    /// 使用指定的值初始化 <see cref="T:System.Security.AccessControl.AccessRule"/> 类的一个新实例。
    /// </summary>
    /// <param name="identity">应用访问规则的标识。此参数必须是可以强制转换为 <see cref="T:System.Security.Principal.SecurityIdentifier"/> 的对象。</param><param name="accessMask">此规则的访问掩码。访问掩码是一个 32 位的匿名位集合，其含义是由每个集成器定义的。</param><param name="isInherited">如果此规则继承自父容器，则为 true。</param><param name="inheritanceFlags">访问规则的继承属性。</param><param name="propagationFlags">继承的访问规则是否自动传播。如果 <paramref name="inheritanceFlags"/> 设置为 <see cref="F:System.Security.AccessControl.InheritanceFlags.None"/>，则将忽略传播标志。</param><param name="type">有效的访问控制类型。</param><exception cref="T:System.ArgumentException"><paramref name="identity"/> 参数的值不能强制转换为 <see cref="T:System.Security.Principal.SecurityIdentifier"/>，或者 <paramref name="type"/> 参数包含无效值。</exception><exception cref="T:System.ArgumentOutOfRangeException"><paramref name="accessMask"/> 参数的值为零，或者 <paramref name="inheritanceFlags"/> 或 <paramref name="propagationFlags"/> 参数包含无法识别的标志值。</exception>
    protected AccessRule(IdentityReference identity, int accessMask, bool isInherited, InheritanceFlags inheritanceFlags, PropagationFlags propagationFlags, AccessControlType type);
    /// <summary>
    /// 获取与此 <see cref="T:System.Security.AccessControl.AccessRule"/> 对象关联的 <see cref="T:System.Security.AccessControl.AccessControlType"/> 对象。
    /// </summary>
    /// 
    /// <returns>
    /// 与此 <see cref="T:System.Security.AccessControl.AccessRule"/> 对象关联的 <see cref="T:System.Security.AccessControl.AccessControlType"/> 对象。
    /// </returns>
    public AccessControlType AccessControlType { get; }
  }

      看来DotNet中实现文件权限设置的操作的类，现在提供几个具体的文件设置操作代码：

   3.获取目录权限列表：

        /// <summary>
        /// 获取目录权限列表
        /// </summary>
        /// <param name="path">目录的路径。</param>
        /// <returns>指示目录的权限列表</returns>
        public IList<FileSystemRights> GetDirectoryPermission(string path)
        {
            try
            {
                if (!DirectoryExists(path))
                    return null;

                IList<FileSystemRights> result = new List<FileSystemRights>();
                var dSecurity = Directory.GetAccessControl(new DirectoryInfo(path).FullName);
                foreach (FileSystemAccessRule rule in dSecurity.GetAccessRules(true, true, typeof(NTAccount)))
                    result.Add(rule.FileSystemRights);

                return result;
            }
            catch (Exception e)
            {
                throw new Exception(e.Message, e);
            }
        }

    4.设置目录权限

        /// <summary>
        ///设置目录权限
        /// </summary>
        /// <param name="path">目录的路径。</param>
        /// <param name="permission">在目录上设置的权限。</param>
        /// <returns>指示是否在目录上应用权限的值。</returns>
        public bool SetDirectoryPermission(string path, FileSystemRights permission)
        {
            try
            {
                if (!DirectoryExists(path))
                    return false;

                var accessRule = new FileSystemAccessRule("Users", permission,
                                            InheritanceFlags.None,
                                            PropagationFlags.NoPropagateInherit,
                                            AccessControlType.Allow);

                var info = new DirectoryInfo(path);
                var security = info.GetAccessControl(AccessControlSections.Access);

                bool result;
                security.ModifyAccessRule(AccessControlModification.Set, accessRule, out result);

                if (!result)
                    return false;

                const InheritanceFlags iFlags = InheritanceFlags.ContainerInherit | InheritanceFlags.ObjectInherit;

                accessRule = new FileSystemAccessRule("Users", permission,
                                            iFlags,
                                            PropagationFlags.InheritOnly,
                                            AccessControlType.Allow);

                security.ModifyAccessRule(AccessControlModification.Add, accessRule, out result);

                if (!result)
                    return false;

                info.SetAccessControl(security);

                return true;
            }
            catch (Exception e)
            {
                throw new Exception(e.Message, e);
            }
        }

   5.设置目录权限列表

        /// <summary>
        /// 设置目录权限列表
        /// </summary>
        /// <param name="path">目录的路径。</param>
        /// <param name="permissions">在目录上设置的权限。</param>
        /// <returns>指示是否在目录上应用权限的值。</returns>
        public bool SetDirectoryPermissions(string path, FileSystemRights[] permissions)
        {
            try
            {
                if (!DirectoryExists(path) || permissions == null || !permissions.Any())
                    return false;

                foreach (var permission in permissions)
                    if (!SetDirectoryPermission(path, permission))
                        return false;

                return true;
            }
            catch (Exception e)
            {
                throw new Exception(e.Message, e);
            }
        }

     以上是对文件权限设置操作的一个简单介绍。