Creating partial methods on compiled LINQ->SQL class...

Question

Hey Everyone --

If I want to compile my LINQ->SQL classes into a DLL to provide to my developers, how can I make it so that they can still hook into the various entity partial methods (OnValidate, for example)? I know that you cannot implement partial methods on a compiled assembly, but any suggestions on how I can extract this behavior (perhaps with events?) would be appreciated.

Answer 1

As far as I am aware, you cannot.

When partial classes are encountered by the compiler, it combines them together to form a complete class. The only way I see your needs being fulfilled is to make your classes inheritable, but with L2S, this may prove to be more trouble than it's worth.

EDIT:

As for events, depending on the size of your L2S class count, it all depends on what you're willing to put in. This solution could work, but will take a long time to get right. Combining Interfaces with events and custom handlers can get you there, just be prepared for the time investment if there are a large number of classes you want accessible.

MSDN - Partial Classes

Answer 2

I would handle this by publishing public events at any point you desire.

Answer 3

You may need to customize this solution for your needs, but a simple way of publishing events from partial methods can be done like so:

partial class LinqClass
{
    public event Action<LinqClass, ChangeAction> OnValidating;

    partial void OnValidate(ChangeAction action)
    {
        if (OnValidating != null)
        {
            OnValidating(this, action);
        }
    }
}

You may or may not need to pass along different parameters, but the Action will support numerous.

Answer 4

If I want to compile my LINQ->SQL classes into a DLL to provide to my developers

I dont think that this is a good idea. There are so many reasons why a LinqToSql Model might want to change. You will likely need to modify your model while discovering new insight into your domain etc.

By creating a seperate DLL "to provide to your developers" you create an artificial boundary that is likely to hinder efficiency in development. Getting a source control system might be more appropriate for what you may try to accomplish (beeing VERY vague here)