WCF服务编程设计规范(4):操作与错误设计(2)

8. Use callback contracts for callbacks only.

只在回调的时候使用回调契约。

9. Avoid mixing regular callbacks and events on the same callback contract.

避免在回调契约上混用常规回调和事件

10. Event operations should be well designed:

事件操作应该设计如下：

a) void return type

避免返回类型

b) No out-parameters

没有out参数

c) Marked as one-way operations

标记为单向操作

11. Avoid using raw callback contracts for event management, and prefer using the publish-subscribe framework.

避免在事件管理中使用原始回调契约，推荐使用发布-订阅框架

12. Always provide explicit methods for callback setup and teardown:

为回调提供清晰的安装(setup)和拆卸 ( teardown)方法

[ServiceContract(CallbackContract　=　typeof(IMyContractCallback))] interface　IMyContract { [OperationContract] void　DoSomething(); [OperationContract] void　Connect(); [OperationContract] void　Disconnect(); } interface　IMyContractCallback {...}

13. Use the type-safe DuplexClientBase<T,C> instead of

DuplexClientBase<T>.

使用类型安全的DuplexClientBase<T,C>代替DuplexClientBase<T>.

14. Use the type-safe DuplexChannelFactory<T,C> instead of

DuplexChannelFactory<T>.

使用类型安全的DuplexChannelFactory<T,C>代替DuplexChannelFactory<T>.

15. When debugging or in intranet deployment of callbacks over the WSDualHttpBinding, use the CallbackBaseAddressBehavior attribute with CallbackPort set to 0:

当调试或在企业局域网部署环境里使用WSDualHttpBinding时，使用CallbackBaseAddressBehavior ，并把 CallbackPort设置0：

[CallbackBaseAddressBehavior(CallbackPort　=　0)] class　MyClient　:　IMyContractCallback {...} Faults

错误

1. Never use a proxy instance after an exception, even if you catch that exception.

不要异常以后使用代理实例，尽管你捕获了异常。

2. Avoid fault contracts and allow WCF to mask the error.

避免错误契约，让WCF来包装错误

3. Do not reuse the callback channel after an exception even if you catch that exception, as the channel may be faulted.

不要在异常后还使用回调通道，尽管你捕获了异常，因为通道可能出于错误状态。

4. Use the FaultContract attribute with exception classes, as opposed to mere serializable types:

在异常类上使用FaultContract属性，而不是可序列化类型上：

//Avoid:避免 [OperationContract] [FaultContract(typeof(double))] double　Divide(double　number1,double　number2); //Correct:正确 [OperationContract] [FaultContract(typeof(DivideByZeroException))] double　Divide(double　number1,double　number2);

5. Avoid lengthy processing such as logging in IErrorHandler.ProvideFault().

避免冗长的处理，比如登入IErrorHandler.ProvideFault().

6. With both service classes and callback classes, set IncludeExceptionDetailInFaults to true in debug sessions, either in the config file or programmatically:

对于服务类和回调类，在调试时，设置IncludeExceptionDetailInFaults为true，配置文件或者编程都可以：

public　class　DebugHelper { public　const　bool　IncludeExceptionDetailInFaults　= #if　DEBUG true; #else false; #endif } [ServiceBehavior(IncludeExceptionDetailInFaults　= DebugHelper.IncludeExceptionDetailInFaults)] class　MyService　:　IMyContract {...}

7. In release builds, do not return unknown exceptions as faults except in diagnostic scenarios.

在发布构建版本里，不要返回不可知的异常做为错误，除非是在调试场景里。