DnsPermissionAttribute Class
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DnsPermissionAttribute Class

 

Specifies permission to request information from Domain Name Servers.

Namespace:   System.Net
Assembly:  System (in System.dll)


<SerializableAttribute>
<AttributeUsageAttribute(AttributeTargets.Assembly Or AttributeTargets.Class Or AttributeTargets.Struct Or AttributeTargets.Constructor Or AttributeTargets.Method,
	AllowMultiple := True, Inherited := False)>
Public NotInheritable Class DnsPermissionAttribute
	Inherits CodeAccessSecurityAttribute

NameDescription
System_CAPS_pubmethodDnsPermissionAttribute(SecurityAction)

Initializes a new instance of the DnsPermissionAttribute class with the specified SecurityAction value.

NameDescription
System_CAPS_pubpropertyAction

Gets or sets a security action.(Inherited from SecurityAttribute.)

System_CAPS_pubpropertyTypeId

When implemented in a derived class, gets a unique identifier for this Attribute.(Inherited from Attribute.)

System_CAPS_pubpropertyUnrestricted

Gets or sets a value indicating whether full (unrestricted) permission to the resource protected by the attribute is declared.(Inherited from SecurityAttribute.)

NameDescription
System_CAPS_pubmethodCreatePermission()

Creates and returns a new instance of the DnsPermission class.(Overrides SecurityAttribute.CreatePermission().)

System_CAPS_pubmethodEquals(Object)

This API supports the product infrastructure and is not intended to be used directly from your code. Returns a value that indicates whether this instance is equal to a specified object.(Inherited from Attribute.)

System_CAPS_pubmethodGetHashCode()

Returns the hash code for this instance.(Inherited from Attribute.)

System_CAPS_pubmethodGetType()

Gets the Type of the current instance.(Inherited from Object.)

System_CAPS_pubmethodIsDefaultAttribute()

When overridden in a derived class, indicates whether the value of this instance is the default value for the derived class.(Inherited from Attribute.)

System_CAPS_pubmethodMatch(Object)

When overridden in a derived class, returns a value that indicates whether this instance equals a specified object.(Inherited from Attribute.)

System_CAPS_pubmethodToString()

Returns a string that represents the current object.(Inherited from Object.)

NameDescription
System_CAPS_pubinterfaceSystem_CAPS_privmethod_Attribute.GetIDsOfNames(Guid, IntPtr, UInt32, UInt32, IntPtr)

Maps a set of names to a corresponding set of dispatch identifiers.(Inherited from Attribute.)

System_CAPS_pubinterfaceSystem_CAPS_privmethod_Attribute.GetTypeInfo(UInt32, UInt32, IntPtr)

Retrieves the type information for an object, which can be used to get the type information for an interface.(Inherited from Attribute.)

System_CAPS_pubinterfaceSystem_CAPS_privmethod_Attribute.GetTypeInfoCount(UInt32)

Retrieves the number of type information interfaces that an object provides (either 0 or 1).(Inherited from Attribute.)

System_CAPS_pubinterfaceSystem_CAPS_privmethod_Attribute.Invoke(UInt32, Guid, UInt32, Int16, IntPtr, IntPtr, IntPtr, IntPtr)

Provides access to properties and methods exposed by an object.(Inherited from Attribute.)

The security information declared by DnsPermissionAttribute is stored in the metadata of the attribute target, which is the class to which the DnsPermissionAttribute is applied. The system then accesses this information at run time. The SecurityAction that is passed to the constructor determines the allowable DNS targets.

These security attributes are used only for Declarative Security. For Imperative Security, use the corresponding DnsPermission class.

Security access is either fully restricted or fully unrestricted. Set the Unrestricted property to true to grant access, or false for no access. Set this property as a named parameter.

For more information about using attributes, see Extending Metadata Using Attributes.

The following example uses DnsPermissionAttribute to apply declarative security to a custom class.

' Uses the DnsPermissionAttribute to restrict access only to those who have permission.
<DnsPermission(SecurityAction.Demand, Unrestricted := true)>  _
Public Class MyClass1

   Public Shared Function GetIPAddress() As IPAddress
      Dim ipAddress As IPAddress = Dns.Resolve("localhost").AddressList(0)
      Return ipAddress
   End Function 'GetIPAddress

   Public Shared Sub Main()
      Try
         ' Grants Access.
         Console.WriteLine(("Access granted" + ControlChars.NewLine + " The local host IP Address is :" + MyClass1.GetIPAddress().ToString()))
      ' Denies Access.
      Catch securityException As SecurityException
         Console.WriteLine("Access denied")
         Console.WriteLine(securityException.ToString())
      End Try
   End Sub 'Main 
End Class '[MyClass1]

.NET Framework
Available since 1.1

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

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