var group = db.Groups.Find(groupId);
if (group != null)
{
group.Users.Add(user); // add user to existing users
db.SaveChanges();
}
或者
user.Groups.Add(group); // add group to existing groups
db.SaveChanges();
如果要替换用户,则只需分配新集合:
group.Users = new List<User> { user };
db.SaveChanges();
如果要从其组中删除用户并将此用户添加到其他组:
var user = db.Users.Find(userId);
user.Groups.Clear();
var group = db.Groups.Find(groupId);
user.Groups.Add(group);
db.SaveChanges();
如果要从组中删除某些用户:
var group = db.Groups.Find(groupId); // get your group
var userToRemove = group.Users.Last(); // select user, e.g. last one
group.Users.Remove(userToRemove); // remove user from group users
db.SaveChanges(); // save changes