The T4 templates are great tool for use. You can generate literally anything with it with comfort of using any .NET code you have available. Code generation (i.e. POCO classes in EFv4), web service proxies, simple DALs, …, all easily available.
But what if your scenario is one step further? You don’t want to use T4 template to generate i.e. code you’ll later compile into your application, but use the T4 template in runtime to generate result your application will later use (i.e. email based on template). Good news is you can do it, and it’s not hard either.
Easiest way is to start with Preprocessed Text Template file type adding to your solution. The file itself is ordinary T4 template you’re familiar with. But if you build your project the result produced isn’t output from template, but the C#/VB code that produces the result if called. Same result can be done by changing Custom Tool into TextTemplatingFilePreprocessor in Properties window of your current T4 template file.
Then you can create instance of this class (it has same name as your template file), setting up properties, if any and calling TransformText method. Pretty easy, isn’t it?
Though Entity Framework 4 doesn’t support bulk action, you can do it. As Matthieu Mezil shows, it’s possible. Nice piece of code, Matthieu.
If you don’t wanna play with it and go straight, you can create a stored procedure for action you need to call it. That’s how I’m doing it. Maybe in next version of EF somebody will think about bulk actions and we’ll see it.
And the v3/v4 is pretty awesome. It’s really going through a lot of options and dealing with it. Worth at least looking at it and quickly thinking about it.
The EDM designer in Entity Framework 4 has a “nice” new feature. You, know in EFv1 you was forced to map all three CUD procedures or nothing. If you didn’t do that, the validation feature told you. If you do the same in EFv4 the validation succeeds. Great, you may think. Finally I can use just procedures I really want (if you whatsoever want to use SPs and tight the logic into database when using ORM) to use and the rest will be generated for me. But nope. In fact the error will be thrown in runtime(!!!).
It’s described in documentation. But I couldn’t help but wonder, who did this decision??? I hate every error in runtime, I like my static compile time checking. It’s much safer, in my opinion.
As it may look like nothing is going on, it’s not true. Next to Firebird 2.5 new protocol features, I’m also working on Entity Framework v4 support. Before I go further, be sure, that all providers written for Entity Framework v1 are also working with v4.
In fact right now all the major improvements in Entity Framework v4 are supported. You can benefit from features available, like the LIKE translation support or plenty of new functions. My personal favorite is TruncateTime (so I can get rid of workaround). The Model First approach is next in a row. At least basic T4 template for start is my aim. The rest could be done by you, simply modifying the template. And also wiring the template into code so you can use it programmatically too. Under the cover, while working on new stuff I’m also finding ways to optimize the code. Luckily the changes will be noticeable. 
The DDEX for Firebird supports Visual Studio 2010 and the full Entity Framework v4 support will be here soon – now you can try a weekly build. Feel free to ask about anything related.
