How to re-use a user control in two Silverlight client applications?

Question

I'm kind of new to Silverlight and I have a solution which has one web project (webApp) that provides remote services and two client applications (client-1 and client-2) that uses these services.

I have created a complex user control in client-1 that view/edit an object retrieved from webApp and I want to re-use this control in client-2.

The problem is, when you reference the service from the client apps, the types are "locally-typed". For example, MyClass defined in the webApp becomes client-1.MyClass in client-1 app. Using exactly the same object (reference) in client-2 app, it is now of type client-2.MyClass

If I create a library to host my control, I will have to add a reference to the web services and I will have a third type, lib.MyClass. We all know that client-1.MyClass, client-2.MyClass and lib.MyClass are all exactly the same class that was generated from web.MyClass but I can't find a way around this problem.

I'm currently looking at sharing the source code of the user control in each client application and having pre-processor defines in each project so I can do this in my user control code file:

#if CLIENT-1
using Client-1.WebAppServiceReference
#end if

#if CLIENT-2
using Client-2.WebAppServiceReference
#end if

Then the method that uses the type MyClass are using the correct "local-type" in each client app. But I'm having problem since there is no pre-processor functionality in the xaml and there is a reference to the application's namespace there that I need to be conditional.

There's got a be an easier way of re-using controls accross silverlight projects, no?? There is no way I'm going to have two copies of the source files for this control, on in each project!!

Thanks!

Answer 1

There are a couple of options that allow you to use shared entity classes across Silverlight projects/WCF service proxies.

1. Use an RIA class library
2. Use a portable class library

If you create your DataContract classes with either of the above, and then reference the library from both your WCF and Silverlight client projects, then the auto-generated code will use a reference to those shared classes (rather than the locally auto-generated classes). This should allow you to re-use your Silverlight UserControls between projects.

The difference between the two approaches is this. If you use the first approach (RIA project), then when you create files named "SomeEntityClass.shared.cs", the ".shared" tells Visual Studio to place a copy of the file in a mirror Silverlight project. The second approach (PCL) is a newer approach -- it allows you to create class libraries that are capable of targeting multiple platforms (.Net, Silverlight, Windows Phone, ...), with a reduced set of core .NET libraries.

Answer 2

I suggest you to dissociate the XAML and graphical stuff from any of Business logics and the like. MVVM is a very good pattern to follow. After that, you can reference your UserControl from second project with the very useful functionality of Visual Studio "Add as Link" Here how you can do it :

For the underlying business, you can make it available for both project, and linking these 2 with it.

Hope it helps