JavaScriptSerializer: JSON serialize và deserialize trong C#

Ngày này JSON đang trở nên phổ biến bởi tính tiện lợi của nó so với XML. Với .Net thư viện JavaScriptSerializer đã được phát triển giúp cho việc chuyển đổi dữ liệu dang định dạng JSON trở nên rất đơn giản.

Chúng ta cùng tìm hiểu một chút về thư viện này qua ví dụ sau:
Mã nguồn
Định nghĩa lớp

[sourcecode language="csharp"]

public class Student
{
public Student()
{
}
public Student(int id, string name)
{
_id = id;
_name = name;
}

int _id;
string _name;
public int ID
{
get
{
return _id;
}

set
{
_id = value;
}
}

public string Name
{
get
{
return _name;
}

set
{
_name = value;
}
}
}
[/sourcecode]

Chuyển đối tượng sang json
[sourcecode language="csharp"]
Student s = new Student(100, "Nguyễn Văn Mít");
string str = serializer.Serialize(s);
Response.Write("Object: " + str);
[/sourcecode]

Kết quả chạy có như sau:
Object: {"ID":100,"Name":"Nguyễn Văn Mít"}

Chuyển từ chuỗi JSON sang đối tượng Student
[sourcecode language="csharp"]
Student s1 = serializer.Deserialize<Student>(str);
Response.Write("<br/>Name: " + s1.Name);
[/sourcecode]

Tương tự như vậy chúng ta cũng có thể chuyển một mảng sang JSON và ngược lại
Tạo một mảng như sau
[sourcecode language="csharp"]
List<Student> list = new List<Student>();
list.Add(new Student(1, "Trần Văn Cam"));
list.Add(new Student(2, "Trần Thanh Long"));
list.Add(new Student(3, "Lê Thị Lựu"));

string strlist = serializer.Serialize(list);
Response.Write("<br/>List: " + strlist);

// in
Response.Write("<br/>List deserialize ");
List<Student> listDe = serializer.Deserialize<List<Student>>(strlist);
foreach (Student item in listDe)
{
Response.Write("<br/>Name: " + item.Name);
}
[/sourcecode]

Chạy lại ví dụ, chúng ta có kết quả
List: [{"ID":1,"Name":"Trần Văn Cam"},{"ID":2,"Name":"Trần Thanh Long"},{"ID":3,"Name":"Lê Thị Lựu"}]

Chuyển một DataTable sang JSON và ngược lại
Kết nối và đọc dữ liệu
[sourcecode language="csharp"]
SqlConnection conn = new SqlConnection("server=.;database=northwind;uid=sa;pwd=sa;");
SqlDataAdapter adp = new SqlDataAdapter("Select employeeid, firstname, lastname, birthdate, photopath from employees", conn);
DataSet ds = new DataSet();
adp.Fill(ds, "Emp");
[/sourcecode]

Chuyển sang JSON
[sourcecode language="csharp"]
List<Dictionary<string, object>> table = new List<Dictionary<string, object>>();
foreach (DataRow r in ds.Tables[0].Rows)
{
Dictionary<string, object> column = new Dictionary<string, object>();
foreach (DataColumn c in ds.Tables[0].Columns)
{
column.Add(c.ColumnName, r[c.ColumnName]);
}
table.Add(column);
}

string dsStr = serializer.Serialize(table);
Response.Write("<br/>Data table: " + dsStr);
[/sourcecode]

Chuyển từ JSON sang DataTable
[sourcecode language="csharp"]
List<Dictionary<string, object>> t2 = serializer.Deserialize<List<Dictionary<string, object>>>(dsStr);
DataTable dt = ds.Tables[0];
dt.Clear();
DataRow deRow;
foreach (Dictionary<string, object> d in t2)
{
deRow = dt.NewRow();
foreach (DataColumn col in dt.Columns)
{
deRow[col.ColumnName] = (d[col.ColumnName] == null ? DBNull.Value : d[col.ColumnName]);
}
dt.Rows.Add(deRow);
}
GridView1.DataSource = dt;
GridView1.DataBind();
[/sourcecode]

Tới đây chạy lại ví dụ có kết quả như sau:

Data table: [{"employeeid":1,"firstname":"Mit","lastname":"Nguyen Van","birthdate":"\/Date(-664786800000)\/","photopath":"http://accweb/emmployees/davolio.bmp"},{"employeeid":2,"firstname":"Fuller","lastname":"Andrew","birthdate":"\/Date(-563871600000)\/","photopath":"http://accweb/emmployees/fuller.bmp"},{"employeeid":3,"firstname":"Janetsssss","lastname":"Leverling","birthdate":"\/Date(-200127600000)\/","photopath":"http://accweb/emmployees/leverling.bmp"},{"employeeid":4,"firstname":"Margaret","lastname":"Peacockdd","birthdate":"\/Date(-1018854000000)\/","photopath":"http://accweb/emmployees/peacock.bmp"},{"employeeid":5,"firstname":"Buchanan","lastname":"Steven","birthdate":"\/Date(-468054000000)\/","photopath":"http://accweb/emmployees/buchanan.bmp"},{"employeeid":6,"firstname":"Suyama","lastname":"Michael","birthdate":"\/Date(1278003600000)\/","photopath":"http://accweb/emmployees/davolio.bmp"},{"employeeid":7,"firstname":"Robert","lastname":"King","birthdate":"\/Date(-302770800000)\/","photopath":"http://accweb/emmployees/davolio.bmp"},{"employeeid":8,"firstname":"Lauradddd","lastname":"Callahan","birthdate":"\/Date(-378025200000)\/","photopath":"http://accweb/emmployees/davolio.bmp"},{"employeeid":9,"firstname":"Anne","lastname":"9","birthdate":"\/Date(-124009200000)\/","photopath":"http://accweb/emmployees/davolio.bmp"},{"employeeid":87,"firstname":"Mr","lastname":"Ben","birthdate":"\/Date(-664786800000)\/","photopath":null},{"employeeid":89,"firstname":"Mrdddd","lastname":"dd","birthdate":"\/Date(-664786800000)\/","photopath":null},{"employeeid":91,"firstname":"Dan","lastname":"Mss","birthdate":"\/Date(-664786800000)\/","photopath":null},{"employeeid":102,"firstname":"Mr","lastname":"Been","birthdate":"\/Date(340822800000)\/","photopath":null},{"employeeid":103,"firstname":"Mr","lastname":"Dan","birthdate":"\/Date(340822800000)\/","photopath":null},{"employeeid":105,"firstname":"Mr","lastname":"Been","birthdate":"\/Date(-664786800000)\/","photopath":null},{"employeeid":106,"firstname":"Mr","lastname":"Dan","birthdate":"\/Date(-664786800000)\/","photopath":null}]

và


Như vậy là cơ bản chúng ta có thể chuyển đổi qua lại giữa JSON và một vài kiểu của .net.


Trong PHP

Xây dựng và sử dụng WCF đơn giản (WCF basic demo for student)

Objectives

1. Create WCF service (host on web server )

2. Using WCF service from window form application

Hits: Step for create and using service

• Create WCF service “Student” with two operations “list()” and “detail(id)”
  1. Define service interface (ServiceContract)
  2. Define class describe detail of student (DataContract)
  3. Define Service by implement from server interface
• Using WCF service from window form application
  1. Find service description of WCF “student”
  2. Reference WCF service
  3. Call operations of student service

Student table

No.	Data field	Data type
1.	S_ID	Int
2.	S_FullName	Text
3.	S_Birthdate	DateTime
4.	S_Address	Text

WCF basic demo 2013 (PDF version of this post)

http://www.mediafire.com/?ji9uiz5l70d8n (Source code of this post)

BEGIN

Open visual studio 2008 (or later)

File -> Create Project

Select as figure

Right click on project -> Add new Item

Select as figure

Right click on project -> Add new Item

Select as figure

Modified class as

 1 namespace students 
 2 { 
 3   [DataContract] 
 4   public class StudentDetail 
 5   { 
 6     [DataMember] 
 7     public int ID; 
 8     [DataMember] 
 9     public string FullName; 
10     [DataMember] 
11     public DateTime Birthdate; 
12     [DataMember] 
13     public string Address; 
14   } 
15 } 
16 
17 Modified IStudent interface as 
18 
19 namespace students 
20 { 
21   [ServiceContract] 
22   public interface IStudent 
23   { 
24     [OperationContract] 
25     DataSet List(); 
26     [OperationContract] 
27     StudentDetail Detail(int ID); 
28   } 
29 } 

Edit Student service as

 1 namespace students 
 2 {
 3   public class Student : IStudent 
 4   { 
 5     public DataSet List() 
 6     { 
 7       DataSet dsS = new DataSet(); 
 8       // insert C# code to get data from student table
 9       return dsS; 
10     } 
11     public StudentDetail Detail(int ID) 
12     { 
13       StudentDetail sDetail = new StudentDetail();
14       return sDetail; 
15     } 
16   }
17 } 
18 

Now right click on service and select view in browser

Right click on solution -> add new project

Select as figure

Design form as

GUI of client

Add service reference as

Modify form load event:

1 wcf.StudentClient proxy; 
2 private void Form1_Load(object sender, EventArgs e) 
3 { 
4   proxy = new WCF_Client.wcf.StudentClient(); 
5 }

Double click on button Find and insert code as

1 private void btnFind_Click(object sender, EventArgs e) 
2 { 
3   wcf.StudentDetail detail = proxy.Detail(Convert.ToInt32(txtID.Text)); 
4   MessageBox.Show("Student id: " + detail.ID + "\nStudent fullname: " + detail.FullName); 
5 }
6 

Double click on button List and insert code as

1 private void btnList_Click(object sender, EventArgs e) 
2 { 
3   dgrStudent.DataSource = proxy.List(); 
4   dgrStudent.DataMember = "student"; 
5 } 

Now run client

Client at runtime

Xem hướng dẫn video trên

Mã nguồn:  http://www.mediafire.com/download/f4l6dpz2wla513w/WebApplication1.rar