WCF面向服务应用程序系列之四：契约设计(MessageContract)
上一章我们介绍了契约设计中的已知类型契约(KnownTypesContract)，这一章我们介绍：消息契约(MessageContract)。
消息契约(MessageContract)：对控制消息头和消息体元素提供了强力支持，支持MessageHeaderAttribute和MessageBodyMemberAttribute属性。可以添加自定义头，控制消息是否被包装(IsWrapped)，以及控制签名与加密(ProtectionLevel)。
开发环境：Visual Studio 2010 + Net Framework 4.0 。
下面通过代码来演示消息契约：
1、新增一个WCF Service Library程序，修改项目名称为MessageContract，删除自动添加的文件。
2、新建Item.cs类，代码如下：
[DataContract(Name
=
"
ItemContract
"
, Namespace
=
"
http://schemas.xinhaijulan.com/demos/MessageContract
"
)]
public
class
Item
{
[DataMember(Name
=
"
IdContract
"
, IsRequired
=
true
, Order
=
0
)]
public
int
Id {
get
;
set
; }
[DataMember(Name
=
"
NameContract
"
, IsRequired
=
true
, Order
=
1
)]
public
string
Name {
get
;
set
; }
[DataMember(Name
=
"
MessageContract
"
, IsRequired
=
true
, Order
=
2
)]
public
string
Message {
get
;
set
; }
}
3、添加消息契约类，代码如下：
[MessageContract(IsWrapped
=
true
, ProtectionLevel
=
ProtectionLevel.EncryptAndSign)]
public
class
SaveRequest
{
[MessageBodyMember]
public
Item Item {
get
;
set
; }
}
[MessageContract(IsWrapped
=
false
)]
public
class
SaveResponse
{
}
[MessageContract(IsWrapped
=
false
)]
public
class
GetRequest
{
[MessageHeader]
public
string
LicenseKey {
get
;
set
; }
}
[MessageContract(IsWrapped
=
false
)]
public
class
GetResponse
{
public
GetResponse()
{
}
public
GetResponse(Item item)
{
this
.Item
=
item;
}
[MessageBodyMember]
public
Item Item {
get
;
set
; }
}
消息契约用到了：MessageContract、MessageHeader、MessageBodyMember标记。
3、新建WCF接口文件IMessageService.cs，代码如下：
[ServiceContract(Name
=
"
MessageContract
"
, Namespace
=
"
http://schemas.xinhaijulan.com/demos/MessageContract
"
)]
public
interface
IMessageService
{
[OperationContract]
SaveResponse SaveItem(SaveRequest requestMessage);
[OperationContract]
GetResponse GetItem(GetRequest requestMessage);
}
4、新建MessageService.cs类，代码如下：
[ServiceBehavior(InstanceContextMode
=
InstanceContextMode.PerSession)]
public
class
MessageService : IMessageService
{
private
Item _item;
public
SaveResponse SaveItem(SaveRequest requestMessage)
{
this
._item
=
requestMessage.Item;
return
new
SaveResponse();
}
public
GetResponse GetItem(GetRequest requestMessage)
{
if
(requestMessage.LicenseKey
!=
"
xinhaijulan
"
)
{
throw
new
FaultException(
"
Invalid license key.
"
);
}
_item.Message
=
"
MessageService is invoked.
"
;
return
new
GetResponse(_item);
}
}
5、修改App.config中的服务名称 、端点契约、服务地址，代码如下：
代码
<?
xml version
=
"
1.0
"
encoding
=
"
utf-8
"
?>
<
configuration
>
<
system.web
>
<
compilation debug
=
"
true
"
/>
</
system.web
>
<!--
When deploying the service library project, the content of the config file must be added to the host
'
s
app.config file. System.Configuration does not support config files
for
libraries.
-->
<
system.serviceModel
>
<
services
>
<
service name
=
"
MessageContract.MessageService
"
>
<
endpoint address
=
""
binding
=
"
wsHttpBinding
"
contract
=
"
MessageContract.IMessageService
"
>
<
identity
>
<
dns value
=
"
localhost
"
/>
</
identity
>
</
endpoint
>
<
endpoint address
=
"
mex
"
binding
=
"
mexHttpBinding
"
contract
=
"
IMetadataExchange
"
/>
<
host
>
<
baseAddresses
>
<
add baseAddress
=
"
http://localhost:8732/Design_Time_Addresses/MessageContract/MessageService/
"
/>
</
baseAddresses
>
</
host
>
</
service
>
</
services
>
<
behaviors
>
<
serviceBehaviors
>
<
behavior
>
<!--
To avoid disclosing metadata information,
set
the value below to
false
and remove the metadata endpoint above before deployment
-->
<
serviceMetadata httpGetEnabled
=
"
True
"
/>
<!--
To receive exception details
in
faults
for
debugging purposes,
set
the value below to
true
. Set to
false
before deployment
to avoid disclosing exception information
-->
<
serviceDebug includeExceptionDetailInFaults
=
"
False
"
/>
</
behavior
>
</
serviceBehaviors
>
</
behaviors
>
</
system.serviceModel
>
</
configuration
>
6、在客户端控制台程序Client中，添加Service Reference，修改名称空间为MessageContract，并添加测试TestMessageContract方法，代码如下：
private
static
void
TestMessageContract()
{
Console.WriteLine(
"
-----------------Test MessageContract Begin-----------------
"
);
MessageContract.MessageContractClient client
=
new
MessageContract.MessageContractClient();
MessageContract.ItemContract item
=
null
;
string
readValue
=
""
;
Console.WriteLine(
"
Input exit to close the client, others continue.
"
);
readValue
=
Console.ReadLine();
while
(readValue
!=
"
exit
"
)
{
item
=
new
MessageContract.ItemContract();
Console.WriteLine(
"
Please input the id:
"
);
item.IdContract
=
GetInt(Console.ReadLine());
Console.WriteLine(
"
You have input item.IdContract:{0}
"
, item.IdContract);
Console.WriteLine(
"
Please input the name:
"
);
item.NameContract
=
Console.ReadLine();
Console.WriteLine(
"
You have input item.NameContract:{0}
"
, item.NameContract);
client.SaveItem(item);
item
=
client.GetItem(
"
xinhaijulan
"
);
if
(item
!=
null
)
{
Console.WriteLine();
Console.WriteLine(
"
Get from server item.IdContract is : {0}
"
, item.IdContract);
Console.WriteLine(
"
Get from server item.NameContract is : {0}
"
, item.NameContract);
Console.WriteLine(
"
Get from server item.MessageContract is : {0}
"
, item.MessageContract);
}
Console.WriteLine(
"
----------------------------------------------
"
);
Console.WriteLine(
"
Input exit to close the client, others continue.
"
);
readValue
=
Console.ReadLine();
}
client.Close();
Console.WriteLine(
"
-----------------Test MessageContract End-----------------
"
);
}
7、设置Client为启动项目，运行调试MessageContract程序，然后，将在控制台看到如下输出：
代码
-----------------
Test MessageContract Begin
-----------------
Input exit to close the client, others
continue
.
Please input the id:
456
You have input item.IdContract:
456
Please input the name:
xinhaijulan
You have input item.NameContract:xinhaijulan
Get from server item.IdContract
is
:
456
Get from server item.NameContract
is
: xinhaijulan
Get from server item.MessageContract
is
: MessageService
is
invoked.
----------------------------------------------
至此，WCF契约设计全部介绍完毕，下一章将介绍WCF的契约版本。
作者：心海巨澜
出处：http:
//xinhaijulan.cnblogs.com
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