save many to many relationship - EF

I've 3 tables: User, Course, UserCourse

how do I save the different courses for a user on table UserCourse using Entity 开发者_运维问答Framework?

Thanks

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Usually, entity framework converts your link table to a direct relationship. That is, you will be able to do this:

someUser.Courses.Add(someCourse);
someUser.Courses.Remove(someOtherCourse);

someCourse.Users.Add(someOtherUser);

At least if your UserCourse table is set up in a way that enables EF to do that. (i.e. only two columns with the two keys of User and Course set as PK)

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UserCourse table should be junction table for EF to understand many-to-many relationship. For example: UserId (PK), CourseId(PK)

After that you can simply add entities to entity collections.

var context = new MyModel();
var user1 = new User { Name = "u1" };
var user2 = new User { Name = "u1" };
context.Users.Add(user1);
context.Users.Add(user2);
var math = new Course { Name = "Math" };
context.Courses.Add(math);
math.Users.Add(user1);
math.Users.Add(user2);
context.SaveChanges();

The same logics for adding course to user: user1.Courses.Add(math);