Best place/way to define context Entity Framework

Question

I think there is two main ways (or more) to define Entity framework Context:

1. Define one Context in the whole App and then use it during all it's life cycle, so here the Context will be disposed after closing the app, I defined this variable in MainWindow then I used it in all my app windows and User Conteols

   public static SC_Context Context = new SC_Context();

2. Define the context every time we want to deal with the database and dispose that context after that. In this way, I make partial classes and write method inside:

   using (SC_Context Context = new SC_Context()) { //Bla Bla Bla }

Actually, I used both ways in many apps, Websites and Windows apps and I saw many samples and developers using them.

Simply my question is: Which is better -using one context for whole app or use one context for each procedure with DB- for App performance and RAM consumption and Why?

Answer 1

According to MSDN (or this blog), you should use the second way, with using statement. When you use using, the compiler automatically creates a try/finally block and calls dispose in the finally block.

Here are some general guidelines when deciding on the lifetime of the context:

1. When working with Web applications, use a context instance per request.
2. When working with Windows Presentation Foundation (WPF) or Windows Forms, use a context instance per form. This lets you use change-tracking functionality that context provides.

In conclusion, the rule is: context per request and context per form lifetimes.