File.SetAccessControl Method (System.IO)

SetAccessControl Method

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Microsoft Visual Studio 2008/.NET Framework 3.5

Other versions are also available for the following:

.NET Framework Class Library

File..::.SetAccessControl Method

Applies access control list (ACL) entries described by a FileSecurity object to the specified file.

Namespace: System.IO
Assembly: mscorlib (in mscorlib.dll)

Syntax

Visual Basic (Declaration)

Public Shared Sub SetAccessControl ( _
    path As String, _
    fileSecurity As FileSecurity _
)

Visual Basic (Usage)

Dim path As String
Dim fileSecurity As FileSecurity

File.SetAccessControl(path, fileSecurity)

public static void SetAccessControl(
    string path,
    FileSecurity fileSecurity
)

Visual C++

public:
static void SetAccessControl(
    String^ path, 
    FileSecurity^ fileSecurity
)

JScript

public static function SetAccessControl(
    path : String, 
    fileSecurity : FileSecurity
)

Parameters

path: Type: System..::.String
A file to add or remove access control list (ACL) entries from.

fileSecurity: Type: System.Security.AccessControl..::.FileSecurity
A FileSecurity object that describes an ACL entry to apply to the file described by the path parameter.

Exceptions

Exception	Condition
IOException	An I/O error occurred while opening the file.
SEHException	The path parameter is nullNothingnullptra null reference (Nothing in Visual Basic).
SystemException	The file could not be found.
UnauthorizedAccessException	The path parameter specified a file that is read-only. -or- This operation is not supported on the current platform. -or- The path parameter specified a directory. -or- The caller does not have the required permission.
ArgumentNullException	The fileSecurity parameter is nullNothingnullptra null reference (Nothing in Visual Basic).

Remarks

The SetAccessControl method applies access control list (ACL) entries to a file that represents the noninherited ACL list.

Caution:
The ACL specified for the fileSecurity parameter replaces the existing ACL for the file. To add permissions for a new user, use the GetAccessControl method to obtain the existing ACL, modify it, and then use SetAccessControl to apply it back to the file.

An ACL describes individuals and/or groups who have, or do not have, rights to specific actions on the given file. For more information, see ACL Technology Overview and How to: Add or Remove Access Control List Entries.

The SetAccessControl method persists only FileSecurity objects that have been modified after object creation. If a FileSecurity object has not been modified, it will not be persisted to a file. Therefore, it is not possible to retrieve a FileSecurity object from one file and reapply the same object to another file.

To copy ACL information from one file to another:

Use the GetAccessControl method to retrieve the FileSecurity object from the source file.
Create a new FileSecurity object for the destination file.
Use the GetSecurityDescriptorBinaryForm or GetSecurityDescriptorSddlForm method of the source FileSecurity object to retrieve the ACL information.
Use the SetSecurityDescriptorBinaryForm or SetSecurityDescriptorSddlForm method to copy the information retrieved in step 3 to the destination FileSecurity object.
Set the destination FileSecurity object to the destination file using the SetAccessControl method.

In NTFS environments, ReadAttributes and ReadExtendedAttributes are granted to the user if the user has ListDirectory rights on the parent folder. To deny ReadAttributes and ReadExtendedAttributes, deny ListDirectory on the parent directory.

Examples

The following code example uses the GetAccessControl and SetAccessControl methods to add and then remove an access control list (ACL) entry from a file. You must supply a valid user or group account to run this example.

Visual Basic

Imports System
Imports System.IO
Imports System.Security.AccessControl



Module FileExample

    Sub Main()
        Try
            Dim fileName As String = "test.xml"

            Console.WriteLine("Adding access control entry for " & fileName)

            ' Add the access control entry to the file.
            AddFileSecurity(fileName, "DomainName\AccountName", _
                FileSystemRights.ReadData, AccessControlType.Allow)

            Console.WriteLine("Removing access control entry from " & fileName)

            ' Remove the access control entry from the file.
            RemoveFileSecurity(fileName, "DomainName\AccountName", _
                FileSystemRights.ReadData, AccessControlType.Allow)

            Console.WriteLine("Done.")
        Catch e As Exception
            Console.WriteLine(e)
        End Try

    End Sub


    ' Adds an ACL entry on the specified file for the specified account.
    Sub AddFileSecurity(ByVal fileName As String, ByVal account As String, _
        ByVal rights As FileSystemRights, ByVal controlType As AccessControlType)

        ' Get a FileSecurity object that represents the 
        ' current security settings.
        Dim fSecurity As FileSecurity = File.GetAccessControl(fileName)

        ' Add the FileSystemAccessRule to the security settings. 
        Dim accessRule As FileSystemAccessRule = _
            New FileSystemAccessRule(account, rights, controlType)

        fSecurity.AddAccessRule(accessRule)

        ' Set the new access settings.
        File.SetAccessControl(fileName, fSecurity)

    End Sub


    ' Removes an ACL entry on the specified file for the specified account.
    Sub RemoveFileSecurity(ByVal fileName As String, ByVal account As String, _
        ByVal rights As FileSystemRights, ByVal controlType As AccessControlType)

        ' Get a FileSecurity object that represents the 
        ' current security settings.
        Dim fSecurity As FileSecurity = File.GetAccessControl(fileName)

        ' Remove the FileSystemAccessRule from the security settings. 
        fSecurity.RemoveAccessRule(New FileSystemAccessRule(account, _
            rights, controlType))

        ' Set the new access settings.
        File.SetAccessControl(fileName, fSecurity)

    End Sub
End Module

using System;
using System.IO;
using System.Security.AccessControl;

namespace FileSystemExample
{
    class FileExample
    {
        public static void Main()
        {
            try
            {
                string fileName = "test.xml";

                Console.WriteLine("Adding access control entry for "
                    + fileName);

                // Add the access control entry to the file.
                AddFileSecurity(fileName, @"DomainName\AccountName",
                    FileSystemRights.ReadData, AccessControlType.Allow);

                Console.WriteLine("Removing access control entry from "
                    + fileName);

                // Remove the access control entry from the file.
                RemoveFileSecurity(fileName, @"DomainName\AccountName",
                    FileSystemRights.ReadData, AccessControlType.Allow);

                Console.WriteLine("Done.");
            }
            catch (Exception e)
            {
                Console.WriteLine(e);
            }
        }

        // Adds an ACL entry on the specified file for the specified account.
        public static void AddFileSecurity(string fileName, string account,
            FileSystemRights rights, AccessControlType controlType)
        {


            // Get a FileSecurity object that represents the
            // current security settings.
            FileSecurity fSecurity = File.GetAccessControl(fileName);

            // Add the FileSystemAccessRule to the security settings.
            fSecurity.AddAccessRule(new FileSystemAccessRule(account,
                rights, controlType));

            // Set the new access settings.
            File.SetAccessControl(fileName, fSecurity);

        }

        // Removes an ACL entry on the specified file for the specified account.
        public static void RemoveFileSecurity(string fileName, string account,
            FileSystemRights rights, AccessControlType controlType)
        {

            // Get a FileSecurity object that represents the
            // current security settings.
            FileSecurity fSecurity = File.GetAccessControl(fileName);

            // Remove the FileSystemAccessRule from the security settings.
            fSecurity.RemoveAccessRule(new FileSystemAccessRule(account,
                rights, controlType));

            // Set the new access settings.
            File.SetAccessControl(fileName, fSecurity);

        }
    }
}

Visual C++

using namespace System;
using namespace System::IO;
using namespace System::Security::AccessControl;

// Adds an ACL entry on the specified file for the specified account.

void AddFileSecurity(String^ fileName, String^ account, 
                        FileSystemRights rights, AccessControlType controlType)
{
    // Get a FileSecurity object that represents the 
    // current security settings.
    FileSecurity^ fSecurity = File::GetAccessControl(fileName);

    // Add the FileSystemAccessRule to the security settings. 
    fSecurity->AddAccessRule(gcnew FileSystemAccessRule
                                   (account,rights, controlType));

    // Set the new access settings.
    File::SetAccessControl(fileName, fSecurity);
}

// Removes an ACL entry on the specified file for the specified account.

void RemoveFileSecurity(String^ fileName, String^ account, 
                        FileSystemRights rights, AccessControlType controlType)
{

    // Get a FileSecurity object that represents the 
    // current security settings.
    FileSecurity^ fSecurity = File::GetAccessControl(fileName);

    // Remove the FileSystemAccessRule from the security settings. 
    fSecurity->RemoveAccessRule(gcnew FileSystemAccessRule
                                      (account,rights, controlType));

    // Set the new access settings.
    File::SetAccessControl(fileName, fSecurity);
}

int main()
{
    try
    {
        String^ fileName = "test.xml";

        Console::WriteLine("Adding access control entry for " + fileName);

        // Add the access control entry to the file.
        AddFileSecurity(fileName, "MYDOMAIN\\MyAccount", 
            FileSystemRights::ReadData, AccessControlType::Allow);

        Console::WriteLine("Removing access control entry from " + fileName);

        // Remove the access control entry from the file.
        RemoveFileSecurity(fileName, "MYDOMAIN\\MyAccount", 
            FileSystemRights::ReadData, AccessControlType::Allow);

        Console::WriteLine("Done.");
    }
    catch (Exception^ ex)
    {
        Console::WriteLine(ex->Message);
    }
}

.NET Framework Security

FileIOPermission
for permission to access the file. Associated enumerations: NoAccess, Change
Security action: Demand

Platforms

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98

The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

Version Information

.NET Framework

Supported in: 3.5, 3.0, 2.0

Reference

File Class

File Members

System.IO Namespace