Managing Entity Framework ObjectContext in ASP.NET

I’m using the Entity Framework for an ASP.NET Web Forms application and I’m wondering how I should deal with ObjectContext and it’s lifetime.
For example, I have an InviteService class that manages invites such as creating and accepting invites. The class itself is in another project/namespace from the Web project.
An InviteUsers() method creates Invite entities for a list of users, calls a repository to save them to the database and mails each user an invite link.

data insert using input output stored procedure

I am creating a web application using ASP.net C#. I have a booking form and I need to insert data into a table using a Stored Procedure. The table has several columns, out of which second column is a computed column. The Stored Procedure is set up to insert the data and fetch the value from the second column after insert. Below is the code for Stored Procedure: