Question

I need to access the current db context in my OnActionFilterExecuting method which receives ActionExecutingContext parameter (filterContext).

I can see it in my local stack while debugging but I don’t know how to access it.

I have tried:

1. filterContext.Controller.db
2. filterContext.Controller(ftvcdl.Controllers.PartController).db

Here is my debug trace: https://i.stack.imgur.com/5CsB1.png

PS: I am new to C# so I don’t fully understand the syntax or how to read the debug stack very well, although I am learning!

Answer 1

You will need to cast the controller to something that provides access to the DB, for example:

var db = ((PartController)filterContext.Controller).DB;

However, you will get issues if you use the attribute on something that isn’t the PartController (or a method in there). You could perhaps improve that by using a base-type or interface instead of PartController.

Another approach would be to use the http-context to convey the DB:

var db = (SomeDbType)filterContext.HttpContext.Items["db"]

and stuff the db into the http-context when you create it (and equally, make sure to dispose it when the request ends)

Finally, you could just have a separate DB-context in the attribute; connection pooling means this may not be a problem:

using(var db = SomeUtilityType.GetDb()) {
     ...
}