Entity can find object and can set the properties of it but it throws “The object cannot be deleted because it was not found in the ObjectStateManager.” exception when I try to delete it.
You can see my story in belong pics.
As you can see, object is not null and entity can find it.

I can see the object whicgh I want to delete in context.

Do you have any suggestion about it?
Thanks,
The problem is that you are disposing the context right after getting the entity. This way Entity Framework cannot keep track of the changes mad to that entity.
Try putting the delete code inside the using statement: