MutexSecurity.RemoveAccessRule(MutexAccessRule) 方法

定义

命名空间:

System.Security.AccessControl

程序集:

System.Threading.AccessControl.dll

搜索如下的访问控制规则：与指定的访问规则具有相同的用户和 AccessControlType（允许或拒绝），并具有兼容的继承和传播标志；如果找到，则从中移除指定访问规则中包含的权限。

public:
 bool RemoveAccessRule(System::Security::AccessControl::MutexAccessRule ^ rule);

public bool RemoveAccessRule (System.Security.AccessControl.MutexAccessRule rule);

override this.RemoveAccessRule : System.Security.AccessControl.MutexAccessRule -> bool

Public Function RemoveAccessRule (rule As MutexAccessRule) As Boolean

参数

rule

MutexAccessRule

指定要搜索的用户和 MutexAccessRule 的 AccessControlType，以及匹配规则（如果找到）必须兼容的一组继承和传播标志。 指定要从兼容规则移除的权限（如果找到）。

返回

Boolean

如果找到一个兼容规则，则为 true；否则为 false。

例外

ArgumentNullException

rule 为 null。

示例

下面的代码示例演示如何使用 RemoveAccessRule 方法从 Allow 对象中的 MutexSecurity 规则中删除权限。 它还显示忽略 中的其他 rule 权限。

该示例创建 一个 MutexSecurity 对象，并添加允许和拒绝当前用户的各种权限的规则。 允许的权限包括 Modify、 ReadPermissions和 Synchronize。 然后，该示例为当前用户（包括 ReadPermissions 和 权限）创建一个新规则，并将该规则与 方法一起使用RemoveAccessRule，从 对象中的AllowMutexSecurity规则中删除ReadPermissionsTakeOwnership。 中rule无关TakeOwnership的权利将被忽略。

注意

此示例不将安全对象附加到 Mutex 对象。 可以在 和 Mutex.SetAccessControl中找到Mutex.GetAccessControl附加安全对象的示例。

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.
        MutexSecurity mSec = new MutexSecurity();

        // Add a rule that grants the current user the 
        // right to enter or release the mutex and read the
        // permissions on the mutex.
        MutexAccessRule rule = new MutexAccessRule(user, 
            MutexRights.Synchronize | MutexRights.Modify
                | MutexRights.ReadPermissions, 
            AccessControlType.Allow);
        mSec.AddAccessRule(rule);

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

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

        // Create a rule that grants the current user 
        // the right to read permissions on the mutex, and
        // take ownership of the mutex. Use this rule to 
        // remove the right to read permissions from the 
        // Allow rule for the current user. The inclusion 
        // of the right to take ownership has no effect.
        rule = new MutexAccessRule(user, 
            MutexRights.TakeOwnership | 
                MutexRights.ReadPermissions, 
            AccessControlType.Allow);
        mSec.RemoveAccessRule(rule);

        ShowSecurity(mSec);
    }

    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);
            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, ReadPermissions, Synchronize


Current access rules:

        User: TestDomain\TestUser
        Type: Deny
      Rights: ChangePermissions

        User: TestDomain\TestUser
        Type: Allow
      Rights: Modify, 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 MutexSecurity()

        ' Add a rule that grants the current user the 
        ' right to enter or release the mutex, and to 
        ' read its permissions.
        Dim rule As New MutexAccessRule(user, _
            MutexRights.Synchronize _
            Or MutexRights.Modify _
            Or MutexRights.ReadPermissions, _
            AccessControlType.Allow)
        mSec.AddAccessRule(rule)

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

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

        ' Create a rule that grants the current user 
        ' the right to read permissions on the mutex, and
        ' take ownership of the mutex. Use this rule to 
        ' remove the right to read permissions from the 
        ' Allow rule for the current user. The inclusion 
        ' of the right to take ownership has no effect.
        rule = New MutexAccessRule(user, _
            MutexRights.TakeOwnership _
            Or MutexRights.ReadPermissions, _
            AccessControlType.Allow)
        mSec.RemoveAccessRule(rule)

        ShowSecurity(mSec)
        
    End Sub 

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

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

            Console.WriteLine("        User: {0}", ar.IdentityReference)
            Console.WriteLine("        Type: {0}", ar.AccessControlType)
            Console.WriteLine("      Rights: {0}", ar.MutexRights)
            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, ReadPermissions, Synchronize
'
'
'Current access rules:
'
'        User: TestDomain\TestUser
'        Type: Deny
'      Rights: ChangePermissions
'
'        User: TestDomain\TestUser
'        Type: Allow
'      Rights: Modify, Synchronize

注解

当前 MutexSecurity 搜索与 具有相同用户且值rule相同的AccessControlType规则。 如果未找到此类规则，则不执行任何操作，并且该方法返回 false。 如果找到匹配的规则，则会检查其继承和兼容性标志是否与 中指定的 rule标志兼容。 如果未找到兼容的规则，则不执行任何操作，并且该方法返回 false。 如果找到具有兼容标志的规则，则会从兼容规则中删除 中指定的 rule 权限，并且该方法返回 true。 如果 rule 指定了未包含在兼容规则中的权限，则不会对这些权限执行任何操作。 如果从兼容规则中删除所有权限，则会从当前 MutexSecurity 对象中删除整个规则。

重要

尽管可以通过使用 AccessRuleFactory 方法创建互斥访问规则来指定继承和传播标志，但不建议这样做。 继承和传播对命名互斥体没有意义，它们使访问规则的维护更加复杂。