EventWaitHandleAccessRule Class

Definition

public ref class EventWaitHandleAccessRule sealed : System::Security::AccessControl::AccessRule

public sealed class EventWaitHandleAccessRule : System.Security.AccessControl.AccessRule

[System.Security.SecurityCritical]
public sealed class EventWaitHandleAccessRule : System.Security.AccessControl.AccessRule

type EventWaitHandleAccessRule = class
    inherit AccessRule

[<System.Security.SecurityCritical>]
type EventWaitHandleAccessRule = class
    inherit AccessRule

Public NotInheritable Class EventWaitHandleAccessRule
Inherits AccessRule

Inheritance

Object

AuthorizationRule

AccessRule

EventWaitHandleAccessRule

Attributes

SecurityCriticalAttribute

Examples

The following code example demonstrates the creation and use of EventWaitHandleAccessRule objects. The example creates an EventWaitHandleSecurity object, adds rules that allow and deny various rights for the current user, and displays the resulting pair of rules. The example then allows new rights for the current user and displays the result, showing that the new rights are merged with the existing Allow rule.

using System;
using System.Threading;
using System.Security.AccessControl;
using System.Security.Principal;

public class Example
{
    public static void Main()
    {
        // Create a string representing the current user.
        string user = Environment.UserDomainName + "\\" + 
            Environment.UserName;

        // Create a security object that grants no access.
        EventWaitHandleSecurity mSec = new EventWaitHandleSecurity();

        // Add a rule that grants the current user the 
        // right to wait on or signal the event.
        EventWaitHandleAccessRule rule = new EventWaitHandleAccessRule(user, 
            EventWaitHandleRights.Synchronize | EventWaitHandleRights.Modify, 
            AccessControlType.Allow);
        mSec.AddAccessRule(rule);

        // Add a rule that denies the current user the 
        // right to change permissions on the event.
        rule = new EventWaitHandleAccessRule(user, 
            EventWaitHandleRights.ChangePermissions, 
            AccessControlType.Deny);
        mSec.AddAccessRule(rule);

        // Display the rules in the security object.
        ShowSecurity(mSec);

        // Add a rule that allows the current user the 
        // right to read permissions on the event. This rule
        // is merged with the existing Allow rule.
        rule = new EventWaitHandleAccessRule(user, 
            EventWaitHandleRights.ReadPermissions, 
            AccessControlType.Allow);
        mSec.AddAccessRule(rule);

        ShowSecurity(mSec);
    }

    private static void ShowSecurity(EventWaitHandleSecurity security)
    {
        Console.WriteLine("\r\nCurrent access rules:\r\n");

        foreach(EventWaitHandleAccessRule ar in 
            security.GetAccessRules(true, true, typeof(NTAccount)))
        {
            Console.WriteLine("        User: {0}", ar.IdentityReference);
            Console.WriteLine("        Type: {0}", ar.AccessControlType);
            Console.WriteLine("      Rights: {0}", ar.EventWaitHandleRights);
            Console.WriteLine();
        }
    }
}

/*This code example produces output similar to following:

Current access rules:

        User: TestDomain\TestUser
        Type: Deny
      Rights: ChangePermissions

        User: TestDomain\TestUser
        Type: Allow
      Rights: Modify, Synchronize


Current access rules:

        User: TestDomain\TestUser
        Type: Deny
      Rights: ChangePermissions

        User: TestDomain\TestUser
        Type: Allow
      Rights: Modify, ReadPermissions, Synchronize
 */

Imports System.Threading
Imports System.Security.AccessControl
Imports System.Security.Principal

Public Class Example

    Public Shared Sub Main()

        ' Create a string representing the current user.
        Dim user As String = Environment.UserDomainName _ 
            & "\" & Environment.UserName

        ' Create a security object that grants no access.
        Dim mSec As New EventWaitHandleSecurity()

        ' Add a rule that grants the current user the 
        ' right to wait on or signal the event.
        Dim rule As New EventWaitHandleAccessRule(user, _
            EventWaitHandleRights.Synchronize _
            Or EventWaitHandleRights.Modify, _
            AccessControlType.Allow)
        mSec.AddAccessRule(rule)

        ' Add a rule that denies the current user the 
        ' right to change permissions on the event.
        rule = New EventWaitHandleAccessRule(user, _
            EventWaitHandleRights.ChangePermissions, _
            AccessControlType.Deny)
        mSec.AddAccessRule(rule)

        ' Display the rules in the security object.
        ShowSecurity(mSec)

        ' Add a rule that allows the current user the 
        ' right to read permissions on the event. This rule
        ' is merged with the existing Allow rule.
        rule = New EventWaitHandleAccessRule(user, _
            EventWaitHandleRights.ReadPermissions, _
            AccessControlType.Allow)
        mSec.AddAccessRule(rule)

        ShowSecurity(mSec)

    End Sub 

    Private Shared Sub ShowSecurity(ByVal security As EventWaitHandleSecurity)
        Console.WriteLine(vbCrLf & "Current access rules:" & vbCrLf)

        For Each ar As EventWaitHandleAccessRule In _
            security.GetAccessRules(True, True, GetType(NTAccount))

            Console.WriteLine("        User: {0}", ar.IdentityReference)
            Console.WriteLine("        Type: {0}", ar.AccessControlType)
            Console.WriteLine("      Rights: {0}", ar.EventWaitHandleRights)
            Console.WriteLine()
        Next

    End Sub
End Class 

'This code example produces output similar to following:
'
'Current access rules:
'
'        User: TestDomain\TestUser
'        Type: Deny
'      Rights: ChangePermissions
'
'        User: TestDomain\TestUser
'        Type: Allow
'      Rights: Modify, Synchronize
'
'
'Current access rules:
'
'        User: TestDomain\TestUser
'        Type: Deny
'      Rights: ChangePermissions
'
'        User: TestDomain\TestUser
'        Type: Allow
'      Rights: Modify, ReadPermissions, Synchronize

Remarks

The EventWaitHandleAccessRule class is one of a set of classes that the .NET Framework provides for managing Windows access control security on named system events. For an overview of these classes, and their relationship to the underlying Windows access control structures, see EventWaitHandleSecurity.

To get a list of the rules currently applied to a named event, use the EventWaitHandle.GetAccessControl method to get an EventWaitHandleSecurity object, and then use its GetAccessRules method to obtain a collection of EventWaitHandleAccessRule objects.

EventWaitHandleAccessRule objects do not map one-to-one with access control entries in the underlying discretionary access control list (DACL). When you get the set of all access rules for an event, the set contains the minimum number of rules currently required to express all the access control entries.

Use EventWaitHandleAccessRule objects to specify the access rights to allow or deny to a user or group. An EventWaitHandleAccessRule object always represents either allowed access or denied access, never both.

To apply a rule to a named system event, use the EventWaitHandle.GetAccessControl method to get the EventWaitHandleSecurity object. Modify the EventWaitHandleSecurity object by using its methods to add the rule, and then use the EventWaitHandle.SetAccessControl method to reattach the security object.

EventWaitHandleAccessRule objects are immutable. Security for an event is modified using the methods of the EventWaitHandleSecurity class to add or remove rules; as you do this, the underlying access control entries are modified.

Constructors

Properties

Methods

Applies to

See also

• EventWaitHandleSecurity