Adding values to “many to many ” relationship in entityframework

Question

I have 3 entities in Sqlserver that I am mapping with the wizard of visual Studio

The three entities are packages categories and packages_categories,where packages_categ

Answer 1

In order to avoid creating new categories you must attach them to the context before you add the new package:

var _packagesContext=new DBPackages();

categoriesList.ForEach(c => _packagesContext.Categories.Attach(c));

_packagesContext.Add(new Packages {
                         packageSid="Sid blaaa.",
                         PackageName="TestPackage",
                         Categories=categoriesList
                     });