Assembly: mscorlib (in mscorlib.dll)
[SerializableAttribute] [ComVisibleAttribute(true)] [AttributeUsageAttribute(AttributeTargets.Assembly|AttributeTargets.Class|AttributeTargets.Struct|AttributeTargets.Constructor|AttributeTargets.Method, AllowMultiple=true, Inherited=false)] public sealed class FileIOPermissionAttribute : CodeAccessSecurityAttribute
/** @attribute SerializableAttribute() */ /** @attribute ComVisibleAttribute(true) */ /** @attribute AttributeUsageAttribute(AttributeTargets.Assembly|AttributeTargets.Class|AttributeTargets.Struct|AttributeTargets.Constructor|AttributeTargets.Method, AllowMultiple=true, Inherited=false) */ public final class FileIOPermissionAttribute extends CodeAccessSecurityAttribute
SerializableAttribute ComVisibleAttribute(true) AttributeUsageAttribute(AttributeTargets.Assembly|AttributeTargets.Class|AttributeTargets.Struct|AttributeTargets.Constructor|AttributeTargets.Method, AllowMultiple=true, Inherited=false) public final class FileIOPermissionAttribute extends CodeAccessSecurityAttribute
Files and directories are specified using absolute paths. When accessing files, a security check is performed when the file is created or opened. The security check is not done again unless the file is closed and reopened. Checking permissions when the file is first accessed minimizes the impact of the security check on application performance because opening a file happens only once, while reading and writing can happen multiple times.
The scope of the declaration that is allowed depends on the SecurityAction that is used.
The security information declared by a security attribute is stored in the metadata of the attribute target and is accessed by the system at run time. Security attributes are used only for declarative security. For imperative security, use the corresponding permission class.
Unrestricted FileIOPermission grants permission for all paths within a file system, including multiple pathnames that can be used to access a single given file. To Deny access to a file, you must Deny all possible paths to the file. For example, if \\server\share is mapped to the network drive X, to Deny access to \\server\share\file, you must Deny \\server\share\file, X:\file and any other path that you can use to access the file.
The following example of a declarative attribute shows the correct way to request FileIOPermission for full access to the specified file and states that you must have at least this permission to run your code.
[assembly:FileIOPermissionAttribute(SecurityAction.RequestMinimum, All="C:\\example\\sample.txt")] //In C#, you must specify that you are using the assembly scope when making a request.
/** @assembly FileIOPermissionAttribute(SecurityAction.RequestMinimum, All = "C:\\example\\sample.txt") */ // In VJ#, you must specify that you are using the assembly scope // when making a request.
The following example shows how to demand that the calling code has unrestricted FileIOPermission at link time. You typically make demands in managed libraries (DLLs) to help protect methods or classes from potentially harmful code.
Windows 98, Windows 2000 SP4, Windows Millennium Edition, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see System Requirements.