Question

I have code structure like that:

var adjective = context.Adjectives.Find(11); //works
var substantive = context.Substantives.Find(11);  //works    
var address = context.Addresses.Where(v => v.ZipCode == new_possible_address.ZipCode).SingleOrDefault();  //works    

var name = context.Names.Find(91); //doesn't work

The last line shows the error message:

“The property ‘Id’ is part of the object’s key information and cannot
be modified.”

I’ve noted if I remove the Where statment, the last Find method works. So:

var adjective = context.Adjectives.Find(11); //works
var substantive = context.Substantives.Find(11);  //works    

var name = context.Names.Find(91); //now works

Also, if I use the debug feature “Set Next Statement” going to adjective or substantive lines right after the execution of “Addresses.Where” line. Both methods stops working too.

Why I can’t use Find and Where method within the same context?

Answer 1

It was a model problem. I had to complete a navigation mapping like that:

modelBuilder.Entity<People>().HasOptional(c => c.Address).WithMany(); 

I needed just this way.