Many to Many Insert

Question

Hello all,

I'm trying to perform a many to many insert with the entity framework. After looking around for a while I decided to post the question.

I have three tables:

Member
Platform
FavouritePlatform (which contains the MemberId and PlatformId)

I am trying to insert a member and add their favourite platforms.

            for (int i = 0; i < favouritePlatformCheckList.Items.Count; i++)
            {
                if (favouritePlatformCheckList.Items[i].Selected)
                {
                    Platform platform = new Platform();
                    platform.EntityKey = 
                        new System.Data.EntityKey("CVGSEntities.Platforms",
                        "Code", favouritePlatformCheckList.Items[i].Value);
                    member.FavouritePlatforms.Add(platform);

                    // Adds the member to the entity context and calls save changes on the context.     

                    memberManager.Add(member);

                }
            }

The code above does not and I believe it is because I am specifying the platform entity key and when its trying to add it it already exists.

Is there anyway to add the favourite platforms without having to do a query for them first? (I have the Ids of the platforms I want to add).

Thanks for any help.