WCF RIA Services - loading data and binding - wcf

Question

I've just been toying around with the new WCF RIA Services Beta for Silverlight this evening. So far it looks nice, but I've come across a few barriers when trying to retrieve data and exposing it to the UI via binding.
First of all, how am I able to get a single integer or string value from my service? Say if I have this method on my domainservice:
public int CountEmployees()
{
return this.ObjectContext.Employees.Count();
}
How am I able to make a call to this and bind the result to, say, a TextBlock?
Also, is there any way to make a custom layout for binding data? I feel a little "limited" to ListBox, DataGrid and such. How is it possible to, i.e., make a Grid with a stackpanel inside and have some TextBlocks showing the bound data? If it's possible at all with WCF RIA Services :)
Thanks a lot in advance.

Answer 1

To do custom methods you can use the Invoke attribute.
In the server side you declare in a domain service like this
[EnableClientAccess]
public class EmployeesService : DomainService
{
[Invoke]
public int CountEmployees()
{
return this.ObjectContext.Employees.Count();
}
}
And in your Client-side you can use it like this
EmployeesContext context = new EmployeesContext();
InvokeOperation<int> invokeOp = context.CountEmployees(OnInvokeCompleted, null);
private void OnInvokeCompleted(InvokeOperation<int> invOp)
{
if (invOp.HasError)
{
MessageBox.Show(string.Format("Method Failed: {0}", invOp.Error.Message));
invOp.MarkErrorAsHandled();
}
else
{
result = invokeOp.Value;
}
}
For the second question, you are not limited with binding. The object you get from your context can be binded with any elements you want.

Answer 2

You can name your class with schema classname.shared.cs and this code will also available in silverlight application.
Using Silverlight/WPF databinding engine you can build any fancy layout using datagrid / listbox containers and regular controls like textbox/label and apply your own style/skin - Example.
EDIT
Shared code cannot contain any database-related functions, only some plain calculations. If you want to retrieve this value from server then you need to make WCF method call.
At serverside you create DomainService implementation:
[EnableClientAccess()]
public class HelloWorld : DomainService
{
public string SayHello()
{
return "Test";
}
}
Then you can use this at client:
HelloWorld context = new HelloWorld();
context.SayHello(x => context_SayHelloCompleted(x), null);
void context_SayHelloCompleted(System.Windows.Ria.InvokeOperation<string> op)
{
HelloTextBlock.Text = op.Value;
}
All dirty work with making HelloWorld class available at Silverlight client is done by Visual Studio. Check hidden generated code folder.
[Invoke] attribute is obsolete in newest release of RIA services.