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; }
}

看了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。