DnsPermissionAttribute Class
Assembly: System (in system.dll)
[SerializableAttribute] [AttributeUsageAttribute(AttributeTargets.Assembly|AttributeTargets.Class|AttributeTargets.Struct|AttributeTargets.Constructor|AttributeTargets.Method, AllowMultiple=true, Inherited=false)] public sealed class DnsPermissionAttribute : CodeAccessSecurityAttribute
/** @attribute SerializableAttribute() */ /** @attribute AttributeUsageAttribute(AttributeTargets.Assembly|AttributeTargets.Class|AttributeTargets.Struct|AttributeTargets.Constructor|AttributeTargets.Method, AllowMultiple=true, Inherited=false) */ public final class DnsPermissionAttribute extends CodeAccessSecurityAttribute
SerializableAttribute AttributeUsageAttribute(AttributeTargets.Assembly|AttributeTargets.Class|AttributeTargets.Struct|AttributeTargets.Constructor|AttributeTargets.Method, AllowMultiple=true, Inherited=false) public final class DnsPermissionAttribute extends CodeAccessSecurityAttribute
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 MyClass{ public static IPAddress GetIPAddress(){ IPAddress ipAddress = Dns.Resolve("localhost").AddressList[0]; return ipAddress; } public static void Main(){ try{ //Grants Access. Console.WriteLine(" Access granted\n The local host IP Address is :" + MyClass.GetIPAddress().ToString()); } // Denies Access. catch(SecurityException securityException){ Console.WriteLine("Access denied"); Console.WriteLine(securityException.ToString()); }
// Uses the DnsPermissionAttribute to restrict access only to those who
// have permission.
/** @attribute DnsPermission(SecurityAction.Demand, Unrestricted = true)
*/
public class MyClass
{
public static IPAddress GetIPAddress()
{
IPAddress ipAddress = (IPAddress)Dns.Resolve(
"localhost").get_AddressList().get_Item(0);
return ipAddress;
} //GetIPAddress
public static void main(String[] args)
{
try {
//Grants Access.
Console.WriteLine(" Access granted\n The local host IP "
+ "Address is :" + MyClass.GetIPAddress().ToString());
}
// Denies Access.
catch (System.Security.SecurityException securityException) {
Console.WriteLine("Access denied");
Console.WriteLine(securityException.ToString());
}
} //main
} //MyClass
System.Attribute
System.Security.Permissions.SecurityAttribute
System.Security.Permissions.CodeAccessSecurityAttribute
System.Net.DnsPermissionAttribute
Windows 98, Windows 2000 SP4, Windows Millennium Edition, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see System Requirements.