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Session : How to Ignore Entity Changes

In order to mark an entity as one that should be ignored for change tracking purposes, use the IgnoreChangesFor method from Advanced session operations.
Unlike the Evict method, performing another Load of that entity won't create a call to the server.
The entity will still take part in the session, but will be ignored for SaveChanges.

Syntax

void IgnoreChangesFor(object entity);

Parameters
entity object Instance of entity for which changes will be ignored.

Example

Employee employee = session.Load<Employee>("employees/1-A");
session.Advanced.IgnoreChangesFor(employee);
employee.Age += 1; //this will be ignored for SaveChanges
session.SaveChanges();