Best practices for sharing DAL between ASP.NET and Silverlight 2

Question

I have an ASP.NET 3.5 e-commerce site that has an admin section. I want to change the ASP.NET-based administration section and rewrite it in Silverlight 2. Silverlight requires asynchronous calls, so I can't just call my existing DAL from a new SL2 application.

What is the best practice for this? Should I create a WCF service and call my existing DAL, or should I put everything in WCF, or just add asynchronous calls to my existing, non-WCF DAL. Look for tips on how to do something like this.

EDIT: So, I read that the best way to do this is to use my existing DAL and create a simple WCF service that references the DAL and terminates the calls. The WCF service does nothing but an intermediary to get to my DAL, but expose it in Silverlight. What if you start from scratch? If you create your DAL as a WCF service to start with and use this service with a WPF client, ASP.NET client, Silverlight client, any other consumer, etc.

Answer 1

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Answer 2

DAL , WCF.

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Answer 3

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Answer 4

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Answer 5

- WCF DAL , T4.

What would be the best practice for using an existing DAL to provide wcf services?