Parent-Child Associations with WCF RIA Domain Services

[Vassili King]

Hello,

I've created a Silverlight WCF RIA solution.  I have DataModels and Domain Services set up. In my Silverlight application, I have a Telerik RadGridView.  The grid works fine if I bind it to the context (some data pulled from a domain service).  However, I cannot figure out a way to create a parent-child association between two contexts.  One of the obstacles on my way is the fact that I'm generating all columns and associations programmatically (the grid is bound to different contexts with differen columns based on different query string values).  Another obstacle is my total lack of knowledge of Telerik Silverlight package.  I've seen demos and whole bunch of articles online, but none seemd to address anything close to what I'm trying to do. 

Below is a more detailed scenario:

Let's say I have two contexts - EmployeeShort (contains only ID, Name and Email) and Employee (contains all the fields of the EmployeeShort context and also a whole bunch of other fields including Location, Phone, Fax, etc.)

I have a simple RadGridView on my Main.xaml page:
 <telerik:RadGridView Name="rgvMainGrid"
                             AutoGenerateColumns="False"
                             IsReadOnly="True"/>

I generate columns and bind data programmatically.

My goal is to have the grid display all records from the EmployeeShort context (which I can easily do), but make every record "extendable" to display a corresponding Employee record with its wide range of employee specific fields (and this is what I can't figure out how to accomplish). 

The GridView demo has a similar scenario - you can see a child record below a parent record displaying more data in it.  However, the data fed into that grid is generated by a parent-child relationship specified in a class.  In my case I have two contexts that can be joined on the ID field (as it is a unique one and shared by both). 

Sample output:

(header)               Name           Email
(parent)                Joe Doe       [e-mail]
(child header)            Name         Email                   Location          Phone  
(child)                        Joe Doe     [e-mail]    Sometown       1(999)123-4567

(another parent)   Joe Smith     [e-mail]
(another parent)   Jane Doe     [e-mail]
...........


I would really appeciate any ideas.

Thank you!

[Vlad]

Hello,

 It will be better to implement the entire logic in your view-model. In this case the grid will not know anything about the data and you will not have to create different templates, use different events, etc. You can check for example this blog post. You can control also what columns should be auto-generated, columns order and names using Data Annotations attributes. 

Greetings,
Vlad
the Telerik team

[Vassili King]

Vlad,

Great approach.  It definitely works.  I've been also thinking about a very similar LINQ approach that would look something like this:

void Main()
{
    var children = new List<child>{
      new child{SSN="777-77-7777", id = 1},
      new child{SSN="888-888-888", id = 2}
     };
    
    var parents = new List<parent>{
      new parent{firstName="First", LastName = "Last", id = 1},
      new parent{firstName="First2", LastName = "Last2", id = 2},
      new parent{firstName="First3", LastName = "Last3", id = 3}
     };
    
    var query = from item in parents
     select new { item.firstName, item.LastName, child = (
      from childItem in children
      where item.id == childItem.id
      select new { childItem.SSN, childItem.Desc }
                            ) };
    
    query.Dump();
}

// Define other methods and classes here for now, but in actuality these are defined in the Entity Model
class child
{
    public string Desc;
    public string SSN;
    public int id;
}
   
class parent
{
    public int id;
    public string firstName;
    public string LastName;
}

The code above (if ran in the LINQPad) results in a grid that can be seen in the attached .jpg file.

Thank you for your help!

Best regards,
Vassili.