WCF开发之已知类型（KnownType）

已知类型（Known types）允许在服务契约中使用多态的行为
在服务操作中暴露基本类型
将已知类型（known types）相关到基本类型（基类类型）自身;特定操作;整个服务契约
采用属性声明或者配置的方式来实现

[KnownType]: 相关到基本类型（基类类型）自身

代码

[DataContract(Namespace  = " htttp://www.cnblogs.com/Charlesliu " )]
[KnownType( typeof (GigInfo))]
[KnownType( typeof (PhotoLink))]
[KnownType( typeof (MP3Link))]
public   class  LinkItem
[DataContract(Namespace  = " htttp://www.cnblogs.com/Charlesliu " )]
public   class  GigInfo: LinkItem
[DataContract(Namespace  = " htttp://www.cnblogs.com/Charlesliu " )]
public   class  PhotoLink: LinkItem
[DataContract(Namespace  = " htttp://www.cnblogs.com/Charlesliu " )]
public   class  MP3Link: LinkItem

 

[ServiceKnownType]: 相关到整个服务契约

代码

[ServiceContract(Name  =   " GigManagerContract " , Namespace  = " http://www.cnblogs.com/Charlesliu " )]
[ServiceKnownType( typeof (GigInfo))]
[ServiceKnownType( typeof (PhotoLink))]
[ServiceKnownType( typeof (MP3Link))]
public   interface  IGigManagerService
{
    [OperationContract]
    void  SaveLink(LinkItem item);
    [OperationContract]
    LinkItem GetLink( string  id);
}

 

[ServiceKnownType]: 相关到特定操作

代码

[ServiceContract(Name  =   " GigManagerContract " , Namespace  = " http://www.cnblogs.com/Charlesliu " )]
public   interface  IGigManagerService
{
    [OperationContract]
    [ServiceKnownType( typeof (GigInfo))]
     void  SaveGig(LinkItem item);
    [OperationContract]
    [ServiceKnownType( typeof (GigInfo))]
    LinkItem GetGig( string  id);
}

 

下面看一个具体的Demo，然后根据代码讲解：

 

ContentTypes 代码

 

using  System;
using  System.Collections.Generic;
using  System.Linq;
using  System.Text;
using  System.Runtime.Serialization;

namespace  ContentTypes
{
    [DataContract(Namespace  =   " http://www.cnblogs.com/Charlesliu " )]
     public   enum  LinkItemCategories
    {
        [EnumMember]
        Gig,
        [EnumMember]
        MP3,
        [EnumMember]
        Photo
    }

    [DataContract(Name  =   " LinkItem_Contract " , Namespace  =   " http://www.cnblogs.com/Charlesliu " )]
    [KnownType( typeof (GigInfo))]
    [KnownType( typeof (PhotoLink))]
    [KnownType( typeof (MP3Link))]
     public   class  LinkItem
    {
         private   long  m_id;
         private   string  m_title;
         private   string  m_description;
         private  DateTime m_dateStart;
         private  DateTime m_dateEnd;
         private   string  m_url;
         private  LinkItemCategories m_category;

        [DataMember(Name  =   " Id_Contract " , IsRequired  =   false , Order  =   0 )]
         public   long  Id
        {
             get  {  return  m_id; }
             set  { m_id  =  value; }
        }

        [DataMember(Name  =   " Title_Contract " , IsRequired  =   true , Order  =   1 )]
         public   string  Title
        {
             get  {  return  m_title; }
             set  { m_title  =  value; }
        }

        [DataMember(Name  =   " Description_Contract " , IsRequired  =   true , Order  =   2 )]
         public   string  Description
        {
             get  {  return  m_description; }
             set  { m_description  =  value; }
        }

        [DataMember(Name  =   " DateStart_Contract " , IsRequired  =   true , Order  =   3 )]
         public  DateTime DateStart
        {
             get  {  return  m_dateStart; }
             set  { m_dateStart  =  value; }
        }

        [DataMember(Name  =   " DateEnd_Contract " , IsRequired  =   false , Order  =   4 )]
         public  DateTime DateEnd
        {
             get  {  return  m_dateEnd; }
             set  { m_dateEnd  =  value; }
        }

        [DataMember(Name  =   " Url_Contract " , IsRequired  =   false , Order  =   5 )]
         public   string  Url
        {
             get  {  return  m_url; }
             set  { m_url  =  value; }
        }

        [DataMember(Name  =   " Category_Contract " , IsRequired  =   false , Order  =   6 )]
         public  LinkItemCategories Category
        {
             get  {  return  m_category; }
             set  { m_category  =  value; }
        }
    }

    [DataContract(Namespace  =   " http://www.cnblogs.com/Charlesliu " )]
     public   class  GigInfo : LinkItem
    {
         public  GigInfo()
        {
             this .Category  =  LinkItemCategories.Gig;
        }
    }

    [DataContract(Namespace  =   " http://www.cnblogs.com/Charlesliu " )]
     public   class  MP3Link : LinkItem
    {
         public  MP3Link()
        {
             this .Category  =  LinkItemCategories.MP3;
        }
    }

    [DataContract(Namespace  =   " http://www.cnblogs.com/Charlesliu " )]
     public   class  PhotoLink : LinkItem
    {
         public  PhotoLink()
        {
             this .Category  =  LinkItemCategories.Photo;
        }
    }
}

 

enum类型可以用[EnumMember]标记，本例中如果不加[KnownType]的相关标记，那么在客户端是看不到子类型的。

GigManagerService 代码

using  System;
using  System.Collections.Generic;
using  System.Linq;
using  System.Runtime.Serialization;
using  System.ServiceModel;
using  System.Text;
using  ContentTypes;

namespace  WcfServiceLibraryDemo
{
    [ServiceBehavior(InstanceContextMode  =  InstanceContextMode.PerSession)]
     public   class  GigManagerService : IGigManagerService
    {

         private  LinkItem m_linkItem;

         #region  IGigManager Members

         public   void  SaveGig(LinkItem item)
        {
            m_linkItem  =  item;
        }

         public  LinkItem GetGig()
        {
             return  m_linkItem;
        }

         #endregion
    }
}

IGigManagerService代码

using  System;
using  System.Collections.Generic;
using  System.Linq;
using  System.Runtime.Serialization;
using  System.ServiceModel;
using  System.Text;
using  ContentTypes;

namespace  WcfServiceLibraryDemo
{
    [ServiceContract(Name  =   " GigManagerServiceContract " , Namespace  =   " http://www.cnblogs.com/Charlesliu " , SessionMode  =  SessionMode.Required)]
     public   interface  IGigManagerService
    {
        [OperationContract(Name  =   " SaveGig " , Action  =   " http://www.cnblogs.com/Charlesliu/GigManagerServiceContract/SaveGig " , ReplyAction  =   " http://www.cnblogs.com/Charlesliu/GigManagerServiceContract/SaveGigResponse " )]
         void  SaveGig(LinkItem item);

        [OperationContract(Name  =   " GetGig " , Action  =   " http://www.cnblogs.com/Charlesliu/GigManagerServiceContract/GetGig " , ReplyAction  =   " http://www.cnblogs.com/Charlesliu/GigManagerServiceContract/GetGigResponse " )]
        LinkItem GetGig();
    }
}

Form1代码

using  System;
using  System.Collections.Generic;
using  System.ComponentModel;
using  System.Data;
using  System.Drawing;
using  System.Linq;
using  System.Text;
using  System.Windows.Forms;
using  WinTest.MyServiceReference;

namespace  WinTest
{
     public   partial   class  Form1 : Form
    {
        MyServiceReference.GigManagerServiceContractClient m_proxy  =   new  WinTest.MyServiceReference.GigManagerServiceContractClient();

         public  Form1()
        {
            InitializeComponent();
        }

         private   void  cmdSave_Click( object  sender, EventArgs e)
        {
            MP3Link item  =   new  MP3Link();

            item.Id_Contract  =   int .Parse( this .txtId.Text);
            item.Title_Contract  =   this .txtTitle.Text;
            item.Description_Contract  =   this .txtDescription.Text;
            item.DateStart_Contract  =   this .dtpStart.Value;
            item.DateEnd_Contract  =   this .dtpEnd.Value;
            item.Url_Contract  =   this .txtUrl.Text;

            m_proxy.SaveGig(item);
        }

         private   void  cmdGet_Click( object  sender, EventArgs e)
        {
            MP3Link item  =  (MP3Link)m_proxy.GetGig();
             if  (item  !=   null )
            {
                 this .txtId.Text  =  item.Id_Contract.ToString();
                 this .txtTitle.Text  =  item.Title_Contract;
                 this .txtDescription.Text  =  item.Description_Contract;

                 if  (item.DateStart_Contract  !=  DateTime.MinValue)
                     this .dtpStart.Value  =  item.DateStart_Contract;
                 if  (item.DateEnd_Contract  !=  DateTime.MinValue)
                     this .dtpEnd.Value  =  item.DateEnd_Contract;

                 this .txtUrl.Text  =  item.Url_Contract;
            }
        }
    }
}

 

看到了吗客户端用的是MP3Link这个类，通过[KnownType]实现了WCF的多态。（完）