Load foreign key properties(Navigation Properities) in Silvelright WCF Ria services.

Before the code,i assume that you have created the relation ship between table in ADO.net Entities.

Here is mine,

 

CREATE TABLE [dbo].[tblRole](
[RoleID] [int] IDENTITY(1,1) NOT NULL,
[RoleName] [nvarchar](50) NOT NULL,
[IsActive] [bit] NOT NULL）

CREATE TABLE [dbo].[tblUser](
[UserID] [int] IDENTITY(1,
[UserName] [nvarchar](50) NOT NULL,
[Password] [nvarchar](50) NOT NULL,
[RoleID] [int] NOT NULL,
[CreatedTime] [datetime] NOT NULL,
[IsActive] [bit] NOT NULL）

 

RoleID will be the foreign Key field.

 

In the entities,you need Create a navigation property against this field.

 

In domain service,

public IQueryable<User> GetUsers() { foreach (User u in ObjectContext.Users) { // load navigation property for all the user objects ObjectContext.LoadProperty<User>(u,a => a.Role); } return ObjectContext.Users; } // return an object [Query(IsComposable = false)] public User CheckUserLogin(string username,string password) { var query = from u in ObjectContext.Users where u.UserName == username && u.Password == password select u; User cu = query.F<a href="/tag/irs/" target="_blank" class="keywords">irs</a>tOrDefault(); if (cu != null) ObjectContext.LoadProperty<User>(cu,a => a.Role); return cu; }

 

 

In silverlight part,you can call the service like this,

 

LoadOperation<User> lu = contex.Load(contex.CheckUserLoginQuery("PYQ","654321")); lu.Completed += (s,e) => { User u = lu.Entities.SingleOrDefault(); if (u == null) Message<a href="/tag/Box/" target="_blank" class="keywords">Box</a>.Show("Invlid user"); else { Message<a href="/tag/Box/" target="_blank" class="keywords">Box</a>.Show(string.Format("Name={0},Role={1}.",u.UserName,u.Role.RoleName)); } };

 

The code above is the sample everywhere people are using,i don't kNow whether there will be a chance that when the service loaded,but the complete event hasn't been attached to the object. For the safe operation,i think the following way is a better choice for doing this. Use CALLBACK function!!!!!

 

contex.Load(contex.CheckUserLoginQuery("PYQ","654321"),delegate(LoadOperation<User> lu) { User u = lu.Entities.SingleOrDefault(); if (u == null) Message<a href="/tag/Box/" target="_blank" class="keywords">Box</a>.Show("NO this user"); else { Message<a href="/tag/Box/" target="_blank" class="keywords">Box</a>.Show(string.Format("Name={0},u.Role.RoleName)); } },null);

 

At last but not least,You must add [Include] attribute to the Navigation Property,or else,the data will not be transfered to SL client.

 

 [XmlIg<a href="/tag/nor/" target="_blank" class="keywords">nor</a>eAttribute()] [SoapIg<a href="/tag/nor/" target="_blank" class="keywords">nor</a>eAttribute()] [DataMemberAttribute()] [EdmRelationshipNavigationPropertyAttribute("My<a href="/tag/Trad/" target="_blank" class="keywords">Trad</a>eModel","RoleUser","Role")] [Include]//this is IMPORTANT!!!!!!!!! public Role Role { get { return ((IEntityWithRelationships)this).RelationshipManager.GetRelatedReference<Role>("My<a href="/tag/Trad/" target="_blank" class="keywords">Trad</a>eModel.RoleUser","Role").Value; } set { ((IEntityWithRelationships)this).RelationshipManager.GetRelatedReference<Role>("My<a href="/tag/Trad/" target="_blank" class="keywords">Trad</a>eModel.RoleUser","Role").Value = value; } }