Deleting a Disconnected Entity in EF 6:

Deleting a disconnected entity is easy. Just set its state to Delete using the Entry() method, as shown below.

// disconnected entity to be deleted
var student = new Student(){ StudentId = 1 };

using (var context = new SchoolDBEntities())
    context.Entry(student).State = System.Data.Entity.EntityState.Deleted;    


In the above example, an instance of the Student entity contains only the StudentId key property. To delete an entity, it only requires a key property. context.Entry(student).State = System.Data.Entity.EntityState.Deleted attaches an entity to a context and sets its state to Deleted. This will execute the following DELETE command in the database.

delete [dbo].[Student]
where ([StudentId] = @0)',N'@0 int',@0=1