Starting at ASP.net 3.5,. NET platform supports two kinds of serialization methods:
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1.DataContractSerializer
2.JavascriptSerializer
The former is mainly serialized according to the Data Contract (DataContract), through a data contract defined as follows:
Code
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<datamember () > _
Public Class Model
<datamember () > Public Property Propertya as String
<datamember () > Public Property Propertyb as String
<ignoredatamember () > Public Property PROPERTYC as String
End Class
This will determine whether the property is serialized according to <DataMember> and <IgnoreDataMember>.
The disadvantage of data contract serialization is that it is necessary to determine whether a property is serialized at the beginning of a data class definition, and that the data model used everywhere may result in the need to be all specified as DataMember. A property that has a default value (such as nothing or null) is also serialized as an unwanted attribute; second, serialization cannot use property aliases, the names defined in the business may be too long, and if a property alias cannot be specified, the bandwidth is wasted, resulting in slower communication between the server side and the client.
Pagemethod is the best use scenario for using the JSON serialization technique to implement asynchronous calls (Ajax calls) on a page without having to write all the logic in a service, and the business logic of the UI can be written in Pagemethod. The Pagemethod can be opened by inserting the following ScriptManager declaration and specifying Enablepagemethods as true.
<asp:scriptmanager id= "ScriptManager1" runat= "Server" enablepagemethods= "true" >
</asp:ScriptManager>
Many people see instances of Pagemethod calls through Ms Ajax, but because Microsoft has been doing asp.net and jquery collaboration experiments in the last two years, we can actually invoke Pagemethod through jquery. However, the call method of jquery cannot use get, as long as the post null JSON object implements the class get call. The script is as follows:
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$.ajax ({
Type: "POST",
URL: "Default.aspx/getjson",
Data: "{}",
ContentType: "Application/json; Charset=utf-8 ",
DataType: "JSON",
Success:function (msg) {
Alert (msg);
}
});
The Pagemethod life method is as follows:
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<webmethod () > _
Public Shared Function Getjson () as String
Dim list as New list (of Model)
For index as Integer = 0 to 1000
Dim M_json as New Model with {. Propertya = "Hello",. Propertyb = "World"}
List. ADD (M_json)
Next
Dim str as String = jsonhelper.serialize (list)
Return str
End Function
[Code]
The model class is defined as follows:
[Code]
<datacontract () > _
Public Class Model
<datamember (Emitdefaultvalue:=false, Isrequired:=false, name:= "A") > Public Property Propertya as String
<datamember (Emitdefaultvalue:=false, Isrequired:=false, name:= "B") > Public Property Propertyb as String
<datamember (Emitdefaultvalue:=false, Isrequired:=false, name:= "C") > Public Property PROPERTYC as String
End Class
The serialized model instance results are:
{"A": "Hello", "B": "World"}
Here to provide you with a more popular online JSON conversion class, using the JavaScriptSerializer, the code is as follows:
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public class Jsonhelper
public Shared Function Serialize (of T) (ByVal obj As T) as String
Dim serializer as New System.Runtime.Serialization.Json.DataContractJsonSerializer (obj. GetType ())
Dim MS as New MemoryStream ()
Serializer. WriteObject (MS, obj)
Dim retVal as String = Encoding.Default.GetString (ms. ToArray ())
return retVal
End Function
Public Shared Function deserialize (of T) (ByVal JSON as String) as T
Dim obj As T = Activator.CreateInstance (Of T) ()
Dim ms as New MemoryStream (Encoding.Unicode.GetBytes (JSON))
Dim Serializer as New System.Runtime.Serialization.Json.DataContractJsonSerializer (obj. GetType ())
obj = CType (serializer. ReadObject (MS), T)
Ms. Close ()
return obj
End Function
End Class
