C#设置文件权限的方法

 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.FullCon<span>本文来源gaodai#ma#com搞*!代#%^码网5</span>trol & ~FileSystemRights.DeleteSubdirectoriesAndFiles))
          fileSystemRights &= ~FileSystemRights.Synchronize;
      }

      return ( int )fileSystemRights;
    }

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

  }

/// <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; }
 }