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ILease 接口

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定义远程处理生存期服务所使用的生存期租约对象。

**命名空间:**System.Runtime.Remoting.Lifetime
**程序集:**mscorlib（在 mscorlib.dll 中）

语法

声明
<ComVisibleAttribute(True)> _
Public Interface ILease
用法
Dim instance As ILease

[ComVisibleAttribute(true)] 
public interface ILease

[ComVisibleAttribute(true)] 
public interface class ILease

/** @attribute ComVisibleAttribute(true) */ 
public interface ILease

ComVisibleAttribute(true) 
public interface ILease

备注

分布式垃圾回收控制何时可以删除服务器应用程序。传统上，分布式垃圾回收使用引用计数和 Ping 进行控制。这在每个对象有少数几个客户端时可以很好地工作，但在每个对象有数千个客户端时效率很低。生存期服务可采用传统分布式垃圾回收器的功能，并在客户端数目增加时能很好地扩展。

生存期服务将租约与每个远程激活的对象关联。当租约过期时，对象将被移除。租约可以指定某对象具有无限长的生存期。

每个 AppDomain 都包含一个管理域中租约的租约管理器。租约管理器定期检查租约是否到期。如果租约已经到期，则可以通过移除其对该租约的引用来取消它，或通过调用该租约的一个或多个主办方来续订它。

租约包含确定其策略的属性以及续订租约时间的方法。租约公开 ILease 接口。

示例

下面的示例由三个程序集组成：一个客户端，一个服务器以及一个由客户端和服务器共享的库。首先编译库，然后是客户端和服务器。下面的命令编译 Visual Basic 文件；要编译 C# 文件，应使用 csc 命令和 .cs 文件扩展名。显示的文件名只是建议性的。

 vbc /t:library ILeaseShare.vb
 vbc /r:ILeaseShare.dll ILeaseServer.vb
 vbc /r:ILeaseShare.dll /r:System.Runtime.Remoting.dll ILeaseClient.vb

没有必要全部使用 Visual Basic 文件或全部使用 C# 文件；一旦完成编译，这些程序集就能一起工作，而不论源代码的语言是什么。若要运行示例，请打开两个命令窗口。首先运行服务器，然后运行客户端。如果将客户端和服务器分别放在不同的文件夹下，就必须在每个文件夹下放置一个共享库的副本。

下面的代码用于共享库。

Imports System
Imports System.Runtime.Remoting
Imports System.Runtime.Remoting.Channels
Imports System.Runtime.Remoting.Lifetime
Imports System.Security.Permissions

Namespace RemotingSamples
   Public Class HelloService
      Inherits MarshalByRefObject

      Public Function HelloMethod(name As String) As String
         Console.WriteLine("Hello " + name)
         Return "Hello " + name
      End Function 'HelloMethod

<SecurityPermissionAttribute(SecurityAction.LinkDemand, Flags:=SecurityPermissionFlag.Infrastructure)> _
      Public Overrides Function InitializeLifetimeService() As Object
         Dim baseLease As ILease = CType(MyBase.InitializeLifetimeService(), ILease)
         If baseLease.CurrentState = LeaseState.Initial Then
            ' For demonstration the initial time is kept small.
            ' in actual scenarios it will be large.
            baseLease.InitialLeaseTime = TimeSpan.FromSeconds(15)
            baseLease.RenewOnCallTime = TimeSpan.FromSeconds(15)
            baseLease.SponsorshipTimeout = TimeSpan.FromMinutes(2)
         End If
         Return baseLease
      End Function 'InitializeLifetimeService
   End Class 'HelloService
End Namespace 'RemotingSamples

using System;
using System.Runtime.Remoting;
using System.Runtime.Remoting.Channels;
using System.Runtime.Remoting.Lifetime;
using System.Security.Permissions;

namespace RemotingSamples
{
   public class HelloService : MarshalByRefObject
   {
      public string HelloMethod(string name)
      {
         Console.WriteLine("Hello " + name);
         return "Hello " + name;
      }

[SecurityPermissionAttribute(SecurityAction.LinkDemand, Flags=SecurityPermissionFlag.Infrastructure)]
      public override object InitializeLifetimeService()
      {
         ILease baseLease = (ILease)base.InitializeLifetimeService();
         if (baseLease.CurrentState == LeaseState.Initial)
         {
            // For demonstration the initial time is kept small.
            // in actual scenarios it will be large.
            baseLease.InitialLeaseTime = TimeSpan.FromSeconds(15);
            baseLease.RenewOnCallTime = TimeSpan.FromSeconds(15);
            baseLease.SponsorshipTimeout = TimeSpan.FromMinutes(2);
         }
         return baseLease;
      }
   }
}

#using <system.dll>
#using <system.runtime.remoting.dll>

using namespace System;
using namespace System::Runtime::Remoting;
using namespace System::Runtime::Remoting::Channels;
using namespace System::Runtime::Remoting::Lifetime;

namespace RemotingSamples
{
   public ref class HelloService: public MarshalByRefObject
   {
   public:
      String^ HelloMethod( String^ name )
      {
         Console::WriteLine( "Hello {0}", name );
         return "Hello {0}",name;
      }

      [System::Security::Permissions::SecurityPermissionAttribute
      (System::Security::Permissions::SecurityAction::LinkDemand, 
      Flags=System::Security::Permissions::SecurityPermissionFlag::Infrastructure)]
      virtual Object^ InitializeLifetimeService() override
      {
         ILease^ baseLease = dynamic_cast<ILease^>(MarshalByRefObject::InitializeLifetimeService());
         if ( baseLease->CurrentState == LeaseState::Initial )
         {
            
            // For demonstration the initial time is kept small.
            // in actual scenarios it will be large.
            baseLease->InitialLeaseTime = TimeSpan::FromSeconds( 15 );
            baseLease->RenewOnCallTime = TimeSpan::FromSeconds( 15 );
            baseLease->SponsorshipTimeout = TimeSpan::FromMinutes( 2 );
         }

         return baseLease;
      }

   };

}

下面的代码用于客户端程序集。

Imports System
Imports System.Runtime.Remoting
Imports System.Runtime.Remoting.Channels
Imports System.Runtime.Remoting.Channels.Tcp
Imports System.Runtime.Remoting.Lifetime

Namespace RemotingSamples


   Class HelloClient

      Shared Sub Main()
         ' Register the channel.
         Dim myChannel As New TcpChannel()
         ChannelServices.RegisterChannel(myChannel)
         RemotingConfiguration.RegisterActivatedClientType( _
                           GetType(HelloService), "Tcp://localhost:8085")

         Dim myTimeSpan As TimeSpan = TimeSpan.FromMinutes(10)

         ' Create a remote object.
         Dim myService As New HelloService()

         Dim myLease As ILease
         myLease = CType(RemotingServices.GetLifetimeService(myService), ILease)
         If myLease Is Nothing Then
            Console.WriteLine("Cannot lease.")
            Return
         End If

         Console.WriteLine("Initial lease time is " & myLease.InitialLeaseTime.ToString())
         Console.WriteLine("Current lease time is " & myLease.CurrentLeaseTime.ToString())
         Console.WriteLine("Renew on call time is " & myLease.RenewOnCallTime.ToString())
         Console.WriteLine("Sponsorship timeout is " & myLease.SponsorshipTimeout.ToString())
         Console.WriteLine("Current lease state is " & myLease.CurrentState.ToString())
         ' Register with a sponser.
         Dim mySponsor As New ClientSponsor()
         myLease.Register(mySponsor)
         Console.WriteLine("Wait for lease to expire (approx. 15 seconds)...")
         System.Threading.Thread.Sleep(myLease.CurrentLeaseTime)
         Console.WriteLine("Current lease time before renewal is " & _
                        myLease.CurrentLeaseTime.ToString())

         ' Renew the lease time.
         myLease.Renew(myTimeSpan)
         Console.WriteLine("Current lease time after renewal is " + _
                        myLease.CurrentLeaseTime.ToString())

         ' Call the Remote method.
         Console.WriteLine("Remote method output is " + myService.HelloMethod("Microsoft"))

         myLease.Unregister(mySponsor)
         GC.Collect()
         GC.WaitForPendingFinalizers()

         ' Register with lease time of 15 minutes.
         myLease.Register(mySponsor, TimeSpan.FromMinutes(15))
         Console.WriteLine("Registered client with lease time of 15 minutes.")
         Console.WriteLine("Current lease time is " + myLease.CurrentLeaseTime.ToString())

         ' Call the Remote method.
         Console.WriteLine("Remote method output is " + myService.HelloMethod("Microsoft"))
         myLease.Unregister(mySponsor)
      End Sub 'Main
   End Class 'HelloClient

End Namespace 'RemotingSamples

using System;
using System.Runtime.Remoting;
using System.Runtime.Remoting.Channels;
using System.Runtime.Remoting.Channels.Tcp;
using System.Runtime.Remoting.Lifetime;

namespace RemotingSamples
{
   class HelloClient
   {
      static void Main()
      {
         // Register the channel.
         TcpChannel myChannel = new TcpChannel ();
         ChannelServices.RegisterChannel(myChannel);
         RemotingConfiguration.RegisterActivatedClientType(
                                typeof(HelloService),"Tcp://localhost:8085");

         TimeSpan myTimeSpan = TimeSpan.FromMinutes(10);

         // Create a remote object.
         HelloService myService = new HelloService();

         ILease myLease;
         myLease = (ILease)RemotingServices.GetLifetimeService(myService);
         if (myLease == null)
         {
            Console.WriteLine("Cannot lease.");
            return;
         }

         Console.WriteLine ("Initial lease time is " + myLease.InitialLeaseTime);
         Console.WriteLine ("Current lease time is " + myLease.CurrentLeaseTime);
         Console.WriteLine ("Renew on call time is " + myLease.RenewOnCallTime);
         Console.WriteLine ("Sponsorship timeout is " + myLease.SponsorshipTimeout);
         Console.WriteLine ("Current lease state is " + myLease.CurrentState.ToString());
         // Register with a sponser.
         ClientSponsor mySponsor = new ClientSponsor();
         myLease.Register(mySponsor);
         Console.WriteLine("Wait for lease to expire (approx. 15 seconds)...");
         System.Threading.Thread.Sleep(myLease.CurrentLeaseTime);
         Console.WriteLine ("Current lease time before renewal is " + myLease.CurrentLeaseTime);

         // Renew the lease time.
         myLease.Renew(myTimeSpan);
         Console.WriteLine ("Current lease time after renewal is " + myLease.CurrentLeaseTime);

         // Call the Remote method.
         Console.WriteLine("Remote method output is " + myService.HelloMethod("Microsoft"));

         myLease.Unregister(mySponsor);
         GC.Collect();
         GC.WaitForPendingFinalizers();

         // Register with lease time of 15 minutes.
         myLease.Register(mySponsor,TimeSpan.FromMinutes(15));
         Console.WriteLine("Registered client with lease time of 15 minutes.");
         Console.WriteLine ("Current lease time is " + myLease.CurrentLeaseTime);

         // Call the Remote method.
         Console.WriteLine("Remote method output is " + myService.HelloMethod("Microsoft"));
         myLease.Unregister(mySponsor);
      }
   }
}

#using <system.dll>
#using <system.runtime.remoting.dll>
#using <ILease_Share.dll>

using namespace System;
using namespace System::Runtime::Remoting;
using namespace System::Runtime::Remoting::Channels;
using namespace System::Runtime::Remoting::Channels::Tcp;
using namespace System::Runtime::Remoting::Lifetime;
using namespace RemotingSamples;

int main()
{
   // Register the channel.
   TcpChannel^ myChannel = gcnew TcpChannel;
   ChannelServices::RegisterChannel( myChannel );
   RemotingConfiguration::RegisterActivatedClientType( HelloService::typeid, "Tcp://localhost:8085" );
   TimeSpan myTimeSpan = TimeSpan::FromMinutes( 10 );

   // Create a remote object.
   HelloService ^ myService = gcnew HelloService;
   ILease^ myLease;
   myLease = dynamic_cast<ILease^>(RemotingServices::GetLifetimeService( myService ));
   if ( myLease == nullptr )
   {
      Console::WriteLine( "Cannot lease." );
      return  -1;
   }

   Console::WriteLine( "Initial lease time is {0}", myLease->InitialLeaseTime );
   Console::WriteLine( "Current lease time is {0}", myLease->CurrentLeaseTime );
   Console::WriteLine( "Renew on call time is {0}", myLease->RenewOnCallTime );
   Console::WriteLine( "Sponsorship timeout is {0}", myLease->SponsorshipTimeout );
   Console::WriteLine( "Current lease state is {0}", myLease->CurrentState );

   // Register with a sponser.
   ClientSponsor^ mySponsor = gcnew ClientSponsor;
   myLease->Register( mySponsor );
   Console::WriteLine( "Wait for lease to expire (approx. 15 seconds)..." );
   System::Threading::Thread::Sleep( myLease->CurrentLeaseTime );
   Console::WriteLine( "Current lease time before renewal is {0}", myLease->CurrentLeaseTime );

   // Renew the lease time.
   myLease->Renew( myTimeSpan );
   Console::WriteLine( "Current lease time after renewal is {0}", myLease->CurrentLeaseTime );

   // Call the Remote method.
   Console::WriteLine( "Remote method output is {0}", myService->HelloMethod( "Microsoft" ) );
   myLease->Unregister( mySponsor );
   GC::Collect();
   GC::WaitForPendingFinalizers();

   // Register with lease time of 15 minutes.
   myLease->Register( mySponsor, TimeSpan::FromMinutes( 15 ) );
   Console::WriteLine( "Registered client with lease time of 15 minutes." );
   Console::WriteLine( "Current lease time is {0}", myLease->CurrentLeaseTime );

   // Call the Remote method.
   Console::WriteLine( "Remote method output is {0}", myService->HelloMethod( "Microsoft" ) );
   myLease->Unregister( mySponsor );
}

下面的代码用于服务器程序集。

Imports System
Imports System.Runtime.Remoting
Imports System.Runtime.Remoting.Channels
Imports System.Runtime.Remoting.Channels.Tcp
Imports System.Runtime.Remoting.Lifetime

Namespace RemotingSamples
   Class HelloServer

      Shared Sub Main()
         Dim myChannel As New TcpChannel(8085)
         ChannelServices.RegisterChannel(myChannel)
         RemotingConfiguration.RegisterActivatedServiceType(GetType(HelloService))
         Console.WriteLine("Server started.")
         Console.WriteLine("Hit enter to terminate...")
         Console.Read()
      End Sub 'Main
   End Class 'HelloServer
End Namespace 'RemotingSamples

using System;
using System.Runtime.Remoting;
using System.Runtime.Remoting.Channels;
using System.Runtime.Remoting.Channels.Tcp;
using System.Runtime.Remoting.Lifetime;


namespace RemotingSamples
{
   class HelloServer
   {
      static void Main()
      {
         TcpChannel myChannel = new TcpChannel (8085);
         ChannelServices.RegisterChannel(myChannel);
         RemotingConfiguration.RegisterActivatedServiceType(typeof(HelloService));
         Console.WriteLine("Server started.");
         Console.WriteLine("Hit enter to terminate...");
         Console.Read();
      }
   }
}

#using <system.dll>
#using <system.runtime.remoting.dll>
#using <ILease_Share.dll>

using namespace System;
using namespace System::Runtime::Remoting;
using namespace System::Runtime::Remoting::Channels;
using namespace System::Runtime::Remoting::Channels::Tcp;
using namespace System::Runtime::Remoting::Lifetime;
using namespace RemotingSamples;

int main()
{
   TcpChannel^ myChannel = gcnew TcpChannel( 8085 );
   ChannelServices::RegisterChannel( myChannel );
   RemotingConfiguration::RegisterActivatedServiceType( HelloService::typeid );
   Console::WriteLine( "Server started." );
   Console::WriteLine( "Hit enter to terminate..." );
   Console::Read();
}

平台

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

.NET Framework 并不是对每个平台的所有版本都提供支持。有关受支持版本的列表，请参见系统要求。

版本信息

.NET Framework

受以下版本支持：2.0、1.1、1.0

请参见

参考

ILease 成员
System.Runtime.Remoting.Lifetime 命名空间