Silverlight提供了几个类来帮助我们方便地转换从WCF获取的JSON数据。它们是:
DataContractJsonSerializer (位于 System.Runtime.Serialization.Json)
JsonObject (位于System.Json,将JSON数据流转换成为可读写的对象)
JsonArray (位于System.Json, 对JSON数据流转换成为JsonObject数组形式,可支持LINQ查询)
注:如果要引用System.Runtime.Serialization.Json名空间里的Json,则必须也引用System.ServiceModel,否则Json会无法使用。
这三类以都支持Stream类型参数,而该参数就是从WCF获取的JSON数据流。使用它们也很简单,首先我们需
要建立一个AJAX型WCF,如下图:
因为我们是获取用户数据,所以将这个WCF命名为UserService.cs:
然后对这个WCF做如下修改:
1.对SVC头文件添加WebServiceHostFactory,如下:
2.注释web.config中的enableWebScript节点,如下:
当然这里所用的WCF为,主要是为了支持形如下面的请求链接方式:
[url]http://localhost:1514/Json_SilverlightWeb/UserService.svc/GetUser[/url]
而下面就是WCF中的代码段:
上面代码中的方法:
GetUser() //对应DataContractJsonSerializer的调用演示
GetUserList(string age) //对应JsonObject的调用演示
GetAllUser() //对应JsonArray的调用演示
分别使用了WebGet属性(位于System.ServiceModel.Web),且ResponseFormat皆为WebMessageFormat.Json
(当然也支持WebMessageFormat.Xml)。而UriTemplate属性为该服务所支持的浏览器链接地址。
当对上面的WCF编译运行之后,我们在浏览器中输入下面地址:
[url]http://localhost:1514/Json_SilverlightWeb/UserService.svc/GetUser[/url] //参见UriTemplate设置
则此时IE会弹出一个保存窗口,如下截图:
而保存到本地的文件内容如下:
看来通过对上述链接的调用,WCF会直接将我们想要的用户信息转换成JSON格式。
注:另个两个链接及其返回JSON内容分别如下所示
[url]http://localhost:1514/Json_SilverlightWeb/UserService.svc/GetUserListByAge/2[/url]
[url]http://localhost:1514/Json_SilverlightWeb/UserService.svc/GetUserList[/url]
下面我们就来看一下Silverlight是何使用来解析上面传回来的JSON数据的.
首先看一下使用DataContractJsonSerializer的示例(详见注释):
因为DataContractJsonSerializer支持将JSON转换成本地的对象类型,所以我们可以像使用普通对象实例
一样。其运行结果如下图所示:
看明白了这段代码之后,再看另两个JSON类的使用方法就简单多了。其DEMO代码如下:
其运行结果如下所示:
最后再看一下JsonArray, 这个类可以看成是JsonObject的一个集合,它支持LINQ查询,其DEMO代码如下:
运行结果如下图所示:
当然在JSON名空间下还有许多不错的类,如果大家有兴趣,我会在以后进行介绍:)
DataContractJsonSerializer (位于 System.Runtime.Serialization.Json)
JsonObject (位于System.Json,将JSON数据流转换成为可读写的对象)
JsonArray (位于System.Json, 对JSON数据流转换成为JsonObject数组形式,可支持LINQ查询)
注:如果要引用System.Runtime.Serialization.Json名空间里的Json,则必须也引用System.ServiceModel,否则Json会无法使用。
这三类以都支持Stream类型参数,而该参数就是从WCF获取的JSON数据流。使用它们也很简单,首先我们需
要建立一个AJAX型WCF,如下图:
因为我们是获取用户数据,所以将这个WCF命名为UserService.cs:
然后对这个WCF做如下修改:
1.对SVC头文件添加WebServiceHostFactory,如下:
<%
@ ServiceHost Language
=
"
C#
"
Debug
=
"
true
"
Service
=
"
UserService
"
Factory = " System.ServiceModel.Activation.WebServiceHostFactory " %>
Factory = " System.ServiceModel.Activation.WebServiceHostFactory " %>
2.注释web.config中的enableWebScript节点,如下:
<
behavior
name
="UserServiceAspNetAjaxBehavior"
>
<!-- <enableWebScript /> -->
</ behavior >
<!-- <enableWebScript /> -->
</ behavior >
当然这里所用的WCF为,主要是为了支持形如下面的请求链接方式:
[url]http://localhost:1514/Json_SilverlightWeb/UserService.svc/GetUser[/url]
而下面就是WCF中的代码段:
[DataContract]
public class UserInfo
{
[DataMember]
public string Name { get ; set ; }
[DataMember]
public string Address { get ; set ; }
[DataMember]
public int Age { get ; set ; }
[DataMember]
public bool IsMember { get ; set ; }
}
[ServiceContract(Namespace = "" )]
[AspNetCompatibilityRequirements(RequirementsMode = AspNetCompatibilityRequirementsMode.Allowed)]
public class UserService
{
List < UserInfo > userList = new List < UserInfo >
{
new UserInfo {Name = " 赵二 " , Address = " 北京 " , Age = 2 , IsMember = true },
new UserInfo {Name = " 张三 " , Address = " 北京 " , Age = 3 , IsMember = false },
new UserInfo {Name = " 李四 " , Address = " 北京 " , Age = 4 , IsMember = true },
new UserInfo {Name = " 王五 " , Address = " 北京 " , Age = 5 , IsMember = false },
};
[OperationContract]
[WebGet(ResponseFormat = WebMessageFormat.Json, UriTemplate = " GetUser " )]
public UserInfo GetUser()
{
return new UserInfo() { Name = " 张三 " , Address = " 北京 " , Age = 3 , IsMember = true };
}
[OperationContract]
[WebGet(ResponseFormat = WebMessageFormat.Json, UriTemplate = " GetUserListByAge/{age} " )]
public UserInfo GetUserListByAge( string age)
{
return (from u in userList
where u.Age == int .Parse(age)
select new UserInfo
{
Age = u.Age,
Name = u.Name,
IsMember = u.IsMember,
Address = u.Address
}).SingleOrDefault();
}
[OperationContract]
[WebGet(ResponseFormat = WebMessageFormat.Json, UriTemplate = " GetUserList " )]
public List < UserInfo > GetUserList()
{
return userList;
}
}
public class UserInfo
{
[DataMember]
public string Name { get ; set ; }
[DataMember]
public string Address { get ; set ; }
[DataMember]
public int Age { get ; set ; }
[DataMember]
public bool IsMember { get ; set ; }
}
[ServiceContract(Namespace = "" )]
[AspNetCompatibilityRequirements(RequirementsMode = AspNetCompatibilityRequirementsMode.Allowed)]
public class UserService
{
List < UserInfo > userList = new List < UserInfo >
{
new UserInfo {Name = " 赵二 " , Address = " 北京 " , Age = 2 , IsMember = true },
new UserInfo {Name = " 张三 " , Address = " 北京 " , Age = 3 , IsMember = false },
new UserInfo {Name = " 李四 " , Address = " 北京 " , Age = 4 , IsMember = true },
new UserInfo {Name = " 王五 " , Address = " 北京 " , Age = 5 , IsMember = false },
};
[OperationContract]
[WebGet(ResponseFormat = WebMessageFormat.Json, UriTemplate = " GetUser " )]
public UserInfo GetUser()
{
return new UserInfo() { Name = " 张三 " , Address = " 北京 " , Age = 3 , IsMember = true };
}
[OperationContract]
[WebGet(ResponseFormat = WebMessageFormat.Json, UriTemplate = " GetUserListByAge/{age} " )]
public UserInfo GetUserListByAge( string age)
{
return (from u in userList
where u.Age == int .Parse(age)
select new UserInfo
{
Age = u.Age,
Name = u.Name,
IsMember = u.IsMember,
Address = u.Address
}).SingleOrDefault();
}
[OperationContract]
[WebGet(ResponseFormat = WebMessageFormat.Json, UriTemplate = " GetUserList " )]
public List < UserInfo > GetUserList()
{
return userList;
}
}
上面代码中的方法:
GetUser() //对应DataContractJsonSerializer的调用演示
GetUserList(string age) //对应JsonObject的调用演示
GetAllUser() //对应JsonArray的调用演示
分别使用了WebGet属性(位于System.ServiceModel.Web),且ResponseFormat皆为WebMessageFormat.Json
(当然也支持WebMessageFormat.Xml)。而UriTemplate属性为该服务所支持的浏览器链接地址。
当对上面的WCF编译运行之后,我们在浏览器中输入下面地址:
[url]http://localhost:1514/Json_SilverlightWeb/UserService.svc/GetUser[/url] //参见UriTemplate设置
则此时IE会弹出一个保存窗口,如下截图:
而保存到本地的文件内容如下:
{
"
Address
"
:
"
北京
"
,
"
Age
"
:
12
,
"
IsMember
"
:
true
,
"
Name
"
:
"
张三
"
}
看来通过对上述链接的调用,WCF会直接将我们想要的用户信息转换成JSON格式。
注:另个两个链接及其返回JSON内容分别如下所示
[url]http://localhost:1514/Json_SilverlightWeb/UserService.svc/GetUserListByAge/2[/url]
{
"
Address
"
:
"
北京
"
,
"
Age
"
:
2
,
"
IsMember
"
:
true
,
"
Name
"
:
"
赵二
"
}
[url]http://localhost:1514/Json_SilverlightWeb/UserService.svc/GetUserList[/url]
[{
"
Address
"
:
"
北京
"
,
"
Age
"
:
2
,
"
IsMember
"
:
false
,
"
Name
"
:
"
赵二
"
},
{ " Address " : " 北京 " , " Age " : 3 , " IsMember " : false , " Name " : " 张三 " },
{ " Address " : " 北京 " , " Age " : 4 , " IsMember " : false , " Name " : " 李四 " },
{ " Address " : " 北京 " , " Age " : 5 , " IsMember " : false , " Name " : " 王五 " }] // 自动转成JSON数组
{ " Address " : " 北京 " , " Age " : 3 , " IsMember " : false , " Name " : " 张三 " },
{ " Address " : " 北京 " , " Age " : 4 , " IsMember " : false , " Name " : " 李四 " },
{ " Address " : " 北京 " , " Age " : 5 , " IsMember " : false , " Name " : " 王五 " }] // 自动转成JSON数组
下面我们就来看一下Silverlight是何使用来解析上面传回来的JSON数据的.
首先看一下使用DataContractJsonSerializer的示例(详见注释):
private
void
GetUserToDataContract_Click(
object
sender, RoutedEventArgs e)
{
Uri serviceUri = new Uri( " [url]http://localhost:1514/Json_SilverlightWeb/UserService.svc/GetUser[/url] " );
WebClient webClient = new WebClient();
webClient.OpenReadCompleted += new OpenReadCompletedEventHandler(webClient_OpenReadCompleted);
webClient.OpenReadAsync(serviceUri);
}
void webClient_OpenReadCompleted( object sender, OpenReadCompletedEventArgs e)
{
// 声明一个UserInfo类型的DataContractJsonSerializer实例
DataContractJsonSerializer serializer = new DataContractJsonSerializer( typeof (UserInfo));
// 获取JSON数据流的信息,并将它转换成为UserInfo实例
UserInfo userInfo = (UserInfo)serializer.ReadObject(e.Result); // e.Result为JSON流数据
// 下面显示userInfo中的数据信息
UserList.Items.Add( string .Format( " Name:{0}, Address:{1}, Age:{2}, IsMember:{3} " ,
userInfo.Name,
userInfo.Address,
userInfo.Age,
userInfo.IsMember));
}
{
Uri serviceUri = new Uri( " [url]http://localhost:1514/Json_SilverlightWeb/UserService.svc/GetUser[/url] " );
WebClient webClient = new WebClient();
webClient.OpenReadCompleted += new OpenReadCompletedEventHandler(webClient_OpenReadCompleted);
webClient.OpenReadAsync(serviceUri);
}
void webClient_OpenReadCompleted( object sender, OpenReadCompletedEventArgs e)
{
// 声明一个UserInfo类型的DataContractJsonSerializer实例
DataContractJsonSerializer serializer = new DataContractJsonSerializer( typeof (UserInfo));
// 获取JSON数据流的信息,并将它转换成为UserInfo实例
UserInfo userInfo = (UserInfo)serializer.ReadObject(e.Result); // e.Result为JSON流数据
// 下面显示userInfo中的数据信息
UserList.Items.Add( string .Format( " Name:{0}, Address:{1}, Age:{2}, IsMember:{3} " ,
userInfo.Name,
userInfo.Address,
userInfo.Age,
userInfo.IsMember));
}
因为DataContractJsonSerializer支持将JSON转换成本地的对象类型,所以我们可以像使用普通对象实例
一样。其运行结果如下图所示:
看明白了这段代码之后,再看另两个JSON类的使用方法就简单多了。其DEMO代码如下:
private
void
GetUserToJsonObject_Click(
object
sender, RoutedEventArgs e)
{
Uri serviceUri = new Uri( "
http: // localhost:1514/Json_SilverlightWeb/UserService.svc/GetUserListByAge/2");
WebClient webClient_JsonObject = new WebClient();
webClient_JsonObject.OpenReadCompleted +=
new OpenReadCompletedEventHandler(webClient_JsonObject_OpenReadCompleted);
webClient_JsonObject.OpenReadAsync(serviceUri);
}
void webClient_JsonObject_OpenReadCompleted( object sender, OpenReadCompletedEventArgs e)
{
JsonObject jsonObject = (JsonObject) JsonObject.Load(e.Result); // e.Result为JSON流数据
// 下面获取JSON对象实例中的数据
UserList.Items.Add( string .Format( " Name:{0}, Address:{1}, Age:{2}, IsMember:{3} " ,
jsonObject[ " Name " ],
jsonObject[ " Address " ],
jsonObject[ " Age " ],
jsonObject[ " IsMember " ]));
}
{
Uri serviceUri = new Uri( "
http: // localhost:1514/Json_SilverlightWeb/UserService.svc/GetUserListByAge/2");
WebClient webClient_JsonObject = new WebClient();
webClient_JsonObject.OpenReadCompleted +=
new OpenReadCompletedEventHandler(webClient_JsonObject_OpenReadCompleted);
webClient_JsonObject.OpenReadAsync(serviceUri);
}
void webClient_JsonObject_OpenReadCompleted( object sender, OpenReadCompletedEventArgs e)
{
JsonObject jsonObject = (JsonObject) JsonObject.Load(e.Result); // e.Result为JSON流数据
// 下面获取JSON对象实例中的数据
UserList.Items.Add( string .Format( " Name:{0}, Address:{1}, Age:{2}, IsMember:{3} " ,
jsonObject[ " Name " ],
jsonObject[ " Address " ],
jsonObject[ " Age " ],
jsonObject[ " IsMember " ]));
}
其运行结果如下所示:
最后再看一下JsonArray, 这个类可以看成是JsonObject的一个集合,它支持LINQ查询,其DEMO代码如下:
private
void
GetUserToJsonArray_Click(
object
sender, RoutedEventArgs e)
{
Uri serviceUri = new Uri( " [url]http://localhost:1514/Json_SilverlightWeb/UserService.svc/GetUserList[/url] " );
WebClient webClient_JsonArray = new WebClient();
webClient_JsonArray.OpenReadCompleted +=
new OpenReadCompletedEventHandler(webClient_JsonArray_OpenReadCompleted);
webClient_JsonArray.OpenReadAsync(serviceUri);
}
void webClient_JsonArray_OpenReadCompleted( object sender, OpenReadCompletedEventArgs e)
{
JsonArray users = (JsonArray)JsonArray.Load(e.Result); // e.Result为JSON流数据
var userlist = from user in users
where user[ " Age " ] > 2
select user;
foreach (JsonObject jsonObject in userlist)
{
UserList.Items.Add( string .Format( " Name:{0}, Address:{1}, Age:{2}, IsMember:{3} " ,
jsonObject[ " Name " ],
jsonObject[ " Address " ],
jsonObject[ " Age " ],
jsonObject[ " IsMember " ]));
}
}
{
Uri serviceUri = new Uri( " [url]http://localhost:1514/Json_SilverlightWeb/UserService.svc/GetUserList[/url] " );
WebClient webClient_JsonArray = new WebClient();
webClient_JsonArray.OpenReadCompleted +=
new OpenReadCompletedEventHandler(webClient_JsonArray_OpenReadCompleted);
webClient_JsonArray.OpenReadAsync(serviceUri);
}
void webClient_JsonArray_OpenReadCompleted( object sender, OpenReadCompletedEventArgs e)
{
JsonArray users = (JsonArray)JsonArray.Load(e.Result); // e.Result为JSON流数据
var userlist = from user in users
where user[ " Age " ] > 2
select user;
foreach (JsonObject jsonObject in userlist)
{
UserList.Items.Add( string .Format( " Name:{0}, Address:{1}, Age:{2}, IsMember:{3} " ,
jsonObject[ " Name " ],
jsonObject[ " Address " ],
jsonObject[ " Age " ],
jsonObject[ " IsMember " ]));
}
}
运行结果如下图所示:
当然在JSON名空间下还有许多不错的类,如果大家有兴趣,我会在以后进行介绍:)
好了,今天的内容就先到这里了。
本文转自 daizhenjun 51CTO博客,原文链接:http://blog.51cto.com/daizhj/83870,如需转载请自行联系原作者