ServiceBehaviorAttribute.InstanceContextMode 属性
定义
重要
一些信息与预发行产品相关,相应产品在发行之前可能会进行重大修改。 对于此处提供的信息,Microsoft 不作任何明示或暗示的担保。
获取或设置指示新服务对象何时创建的值。
public:
property System::ServiceModel::InstanceContextMode InstanceContextMode { System::ServiceModel::InstanceContextMode get(); void set(System::ServiceModel::InstanceContextMode value); };
public System.ServiceModel.InstanceContextMode InstanceContextMode { get; set; }
member this.InstanceContextMode : System.ServiceModel.InstanceContextMode with get, set
Public Property InstanceContextMode As InstanceContextMode
属性值
InstanceContextMode 值之一;默认值为 PerSession。
例外
示例
下面的代码示例演示了 ServiceBehaviorAttribute 属性。
BehaviorService
类使用 ServiceBehaviorAttribute 属性以指示:
在 UI 线程上调用实现方法。
每个会话都有一个服务对象。
服务是单线程服务,不支持可重入调用。
而且,在操作级别,OperationBehaviorAttribute 值指示 TxWork
方法将自动登记到流事务中或创建新事务来做这项工作,并指示如果没有发生未经处理的异常,则自动提交此事务。
using System;
using System.ServiceModel;
using System.Transactions;
namespace Microsoft.WCF.Documentation
{
[ServiceContract(
Namespace="http://microsoft.wcf.documentation",
SessionMode=SessionMode.Required
)]
public interface IBehaviorService
{
[OperationContract]
string TxWork(string message);
}
// Note: To use the TransactionIsolationLevel property, you
// must add a reference to the System.Transactions.dll assembly.
/* The following service implementation:
* -- Processes messages on one thread at a time
* -- Creates one service object per session
* -- Releases the service object when the transaction commits
*/
[ServiceBehavior(
ConcurrencyMode=ConcurrencyMode.Single,
InstanceContextMode=InstanceContextMode.PerSession,
ReleaseServiceInstanceOnTransactionComplete=true
)]
public class BehaviorService : IBehaviorService, IDisposable
{
Guid myID;
public BehaviorService()
{
myID = Guid.NewGuid();
Console.WriteLine(
"Object "
+ myID.ToString()
+ " created.");
}
/*
* The following operation-level behaviors are specified:
* -- The executing transaction is committed when
* the operation completes without an
* unhandled exception
* -- Always executes under a flowed transaction.
*/
[OperationBehavior(
TransactionAutoComplete = true,
TransactionScopeRequired = true
)]
[TransactionFlow(TransactionFlowOption.Mandatory)]
public string TxWork(string message)
{
// Do some transactable work.
Console.WriteLine("TxWork called with: " + message);
// Display transaction information.
TransactionInformation info = Transaction.Current.TransactionInformation;
Console.WriteLine("The distributed tx ID: {0}.", info.DistributedIdentifier);
Console.WriteLine("The tx status: {0}.", info.Status);
return String.Format("Hello. This was object {0}.",myID.ToString()) ;
}
public void Dispose()
{
Console.WriteLine(
"Service "
+ myID.ToString()
+ " is being recycled."
);
}
}
}
Imports System.ServiceModel
Imports System.Transactions
Namespace Microsoft.WCF.Documentation
<ServiceContract(Namespace:="http://microsoft.wcf.documentation", SessionMode:=SessionMode.Required)> _
Public Interface IBehaviorService
<OperationContract> _
Function TxWork(ByVal message As String) As String
End Interface
' Note: To use the TransactionIsolationLevel property, you
' must add a reference to the System.Transactions.dll assembly.
' The following service implementation:
' * -- Processes messages on one thread at a time
' * -- Creates one service object per session
' * -- Releases the service object when the transaction commits
'
<ServiceBehavior(ConcurrencyMode:=ConcurrencyMode.Single, InstanceContextMode:=InstanceContextMode.PerSession, _
ReleaseServiceInstanceOnTransactionComplete:=True)> _
Public Class BehaviorService
Implements IBehaviorService, IDisposable
Private myID As Guid
Public Sub New()
myID = Guid.NewGuid()
Console.WriteLine("Object " & myID.ToString() & " created.")
End Sub
'
' * The following operation-level behaviors are specified:
' * -- The executing transaction is committed when
' * the operation completes without an
' * unhandled exception
' * -- Always executes under a flowed transaction.
'
<OperationBehavior(TransactionAutoComplete:=True, TransactionScopeRequired:=True), TransactionFlow(TransactionFlowOption.Mandatory)> _
Public Function TxWork(ByVal message As String) As String Implements IBehaviorService.TxWork
' Do some transactable work.
Console.WriteLine("TxWork called with: " & message)
' Display transaction information.
Dim info As TransactionInformation = Transaction.Current.TransactionInformation
Console.WriteLine("The distributed tx ID: {0}.", info.DistributedIdentifier)
Console.WriteLine("The tx status: {0}.", info.Status)
Return String.Format("Hello. This was object {0}.", myID.ToString())
End Function
Public Sub Dispose() Implements IDisposable.Dispose
Console.WriteLine("Service " & myID.ToString() & " is being recycled.")
End Sub
End Class
End Namespace
为了正确执行下面的代码示例,基础绑定必须支持流事务。 例如,若要使用 WSHttpBinding 支持流事务,请在代码或应用程序配置文件中将 TransactionFlow 属性设置为 true
。 下面的代码示例演示上述示例的配置文件。
<configuration>
<system.serviceModel>
<services>
<service
name="Microsoft.WCF.Documentation.BehaviorService"
behaviorConfiguration="metadataAndDebugEnabled"
>
<host>
<baseAddresses>
<add baseAddress="http://localhost:8080/SampleService"/>
</baseAddresses>
</host>
<!--
Note:
This example code uses the WSHttpBinding to support transactions using the
WS-AtomicTransactions (WS-AT) protocol. WSHttpBinding is configured to use the
protocol, but the protocol is not enabled on some computers. Use the xws_reg -wsat+
command to enable the WS-AtomicTransactions protocol in the MSDTC service.
-->
<endpoint
contract="Microsoft.WCF.Documentation.IBehaviorService"
binding="wsHttpBinding"
bindingConfiguration="wsHttpBindingWithTXFlow"
address="http://localhost:8080/BehaviorService"
/>
<endpoint
contract="Microsoft.WCF.Documentation.IBehaviorService"
binding="netTcpBinding"
bindingConfiguration="netTcpBindingWithTXFlow"
address="net.tcp://localhost:8081/BehaviorService"
/>
<endpoint
address="mex"
binding="mexHttpBinding"
contract="IMetadataExchange"
/>
</service>
</services>
<behaviors>
<serviceBehaviors>
<behavior name="metadataAndDebugEnabled">
<serviceDebug
includeExceptionDetailInFaults="true"
/>
<serviceMetadata
httpGetEnabled="true"
httpGetUrl=""
/>
</behavior>
</serviceBehaviors>
</behaviors>
<!-- binding configuration - configures a WSHttpBinding to require transaction flow -->
<bindings>
<wsHttpBinding>
<binding name="wsHttpBindingWithTXFlow" transactionFlow="true" />
</wsHttpBinding>
<netTcpBinding>
<binding name="netTcpBindingWithTXFlow" transactionFlow="true" />
</netTcpBinding>
</bindings>
</system.serviceModel>
</configuration>
注解
使用 InstanceContextMode 属性,可以指定新服务对象何时创建。 如果服务对象没有直接连接到通信通道,服务对象的生存期将与客户端和服务应用程序之间的通道的生存期无关。 默认值 PerSession 会构造服务应用程序,以在客户端和服务应用程序之间建立新的通信会话时,创建新的服务对象。 相同会话中的后续调用由同一个对象处理。
PerSession 指示每一个服务对象都从一个客户端通道处理请求。
注意
InstanceContextMode 属性可与其他一些设置进行交互。 例如,如果 InstanceContextMode 值设置为 Single,那么结果是您的服务一次只能处理一条消息,除非您还将 ConcurrencyMode 值设置为 Multiple。 此属性与 ServiceContractAttribute.SessionMode 属性结合时也可生成行为。 有关详细信息,请参阅 会话、实例化和并发。
对于单一实例生存期行为(例如,如果主机应用程序调用 ServiceHost 构造函数并传递一个对象以用作该服务),该服务类必须将 InstanceContextMode 设置为 Single
,否则运行时会引发异常。