Question

For the following code, getting the message:

Cannot attach an entity that already exists.

C# code:

var con = (from c in cmsContentTable where c.ContentName == contentId select c).FirstOrDefault();
cmsContentTable.Attach(con);
con.ContentData = "New Value";
cmsContentTable.Context.SubmitChanges(); 

Why is it giving this error – Is this because a reference to con was already made
when

var con = (from c in cmsContentTable where c.ContentName == contentId select c).FirstOrDefault();

was done?

Answer 1

Since you are already getting the item from the table:

var con = (from c in cmsContentTable where c.ContentName == contentId select    c).FirstOrDefault();

The context is already ‘attached’ to the object. This is true whenever you pull an already existing object from a table.

If you remove the line:

cmsContentTable.Attach(con);

You should be fine.

A more helpful message would be “Cannot attach to an entity that is already attached to a context”, as that is what is actually happening.