Question

In LINQ to SQL, is it possible to check to see if an entity is already part of the data context before trying to attach it?

A little context if it helps…

I have this code in my global.asax as a helper method. Normally, between requests, this isn’t a problem. But right after signing in, this is getting called more than once, and the second time I end up trying to attach the Member object in the same unit of work where it was created.

private void CheckCurrentUser() {     if (!HttpContext.Current.User.Identity.IsAuthenticated)     {         AppHelper.CurrentMember = null;         return;     }      IUserService userService = new UserService();      if (AppHelper.CurrentMember != null)         userService.AttachExisting(AppHelper.CurrentMember);     else         AppHelper.CurrentMember = userService.GetMember(             HttpContext.Current.User.Identity.Name,             AppHelper.CurrentLocation); } 

Answer 1

I believe there are two methods to do this.

DataContext.TableName.Contains(Item) 

or we use the id field. If the item is inserted in the Database, then it will be assigned a row.

if(Item.id == 0)    DataContext.Insert(Item) else    DataContext.Update(Item)