MutexAccessRule Constructor (String, MutexRights, AccessControlType)

Initializes a new instance of the MutexAccessRule class, specifying the name of the user or group the rule applies to, the access rights, and whether the specified access rights are allowed or denied.

Namespace:  System.Security.AccessControl
Assembly:  mscorlib (in mscorlib.dll)

public MutexAccessRule(
	string identity,
	MutexRights eventRights,
	AccessControlType type


Type: System.String

The name of the user or group the rule applies to.

Type: System.Security.AccessControl.MutexRights

A bitwise combination of MutexRights values specifying the rights allowed or denied.

Type: System.Security.AccessControl.AccessControlType

One of the AccessControlType values specifying whether the rights are allowed or denied.


eventRights specifies an invalid value.


type specifies an invalid value.


eventRights is zero.


identity is null.


identity is a zero-length string.


identity is longer than 512 characters.

To wait on a Mutex (by calling the WaitOne, WaitAny or WaitAll method), a user must have MutexRights.Synchronize access. To release the mutex, by calling the ReleaseMutex methods, the user must have MutexRights.Modify access.

This constructor is equivalent to creating an NTAccount object, by passing identity to the NTAccount.NTAccount(String) constructor, and passing the newly created NTAccount object to the MutexAccessRule(IdentityReference, MutexRights, AccessControlType) constructor.

The following code example demonstrates the use of this constructor to create MutexAccessRule objects. The example creates a MutexSecurity 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.


This example does not attach the security object to a Mutex object. Examples that attach security objects can be found in Mutex.GetAccessControl and Mutex.SetAccessControl.

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 + "\\" + 

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

        // Add a rule that grants the current user the  
        // right to enter or release the mutex.
        MutexAccessRule rule = new MutexAccessRule(user, 
            MutexRights.Synchronize | MutexRights.Modify, 

        // Add a rule that denies the current user the  
        // right to change permissions on the mutex.
        rule = new MutexAccessRule(user, 

        // Display the rules in the security object.

        // Add a rule that allows the current user the  
        // right to read permissions on the mutex. This rule 
        // is merged with the existing Allow rule.
        rule = new MutexAccessRule(user, 


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

        foreach(MutexAccessRule 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.MutexRights);

/*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

.NET Framework

Supported in: 4.6, 4.5, 4, 3.5, 3.0, 2.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1
Was this page helpful?
(1500 characters remaining)
Thank you for your feedback
© 2015 Microsoft