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

概述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] [nv

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.FirstOrDefault(); 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) MessageBox.Show("InvlID user"); else { MessageBox.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) MessageBox.Show("NO this user"); else { MessageBox.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.

 

 [XmlignoreAttribute()] [SoAPIgnoreAttribute()] [DataMemberAttribute()] [EdmRelationshipNavigationPropertyAttribute("MyTradeModel","RoleUser","Role")] [Include]//this is important!!!!!!!!! public Role Role { get { return ((IEntityWithRelationships)this).RelationshipManager.GetRelatedReference<Role>("MyTradeModel.RoleUser","Role").Value; } set { ((IEntityWithRelationships)this).RelationshipManager.GetRelatedReference<Role>("MyTradeModel.RoleUser","Role").Value = value; } }

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