Session: How to check if there are any changes on a session?

Property indicates if session contains any changes. That is if there are any new, changed or deleted entities.

Syntax

bool HasChanges { get; }

Example

using (IDocumentSession session = store.OpenSession())
{
	Assert.False(session.Advanced.HasChanges);

	session.Store(new Employee
					  {
						  FirstName = "John",
						  LastName = "Doe"
					  });

	Assert.True(session.Advanced.HasChanges);
}

Method returns all changes for each entity stored within session. Including name of the field/property that changed, its old and new value and change type.

Syntax

IDictionary<string, DocumentsChanges[]> WhatChanged();

Example I

using (IDocumentSession session = store.OpenSession())
{
	session.Store(new Employee
	{
		FirstName = "Joe",
		LastName = "Doe"
	});

	IDictionary<string, DocumentsChanges[]> changes = session.Advanced.WhatChanged();
	DocumentsChanges[] employeeChanges = changes["employees/1"];
	DocumentsChanges.ChangeType change = employeeChanges[0].Change; // DocumentsChanges.ChangeType.DocumentAdded
}

Example II

using (IDocumentSession session = store.OpenSession())
{
	Employee employee = session.Load<Employee>("employees/1"); // 'Joe Doe'
	employee.FirstName = "John";
	employee.LastName = "Shmoe";

	IDictionary<string, DocumentsChanges[]> changes = session.Advanced.WhatChanged();
	DocumentsChanges[] employeeChanges = changes["employees/1"];
	DocumentsChanges change1 = employeeChanges[0]; // DocumentsChanges.ChangeType.FieldChanged
	DocumentsChanges change2 = employeeChanges[1]; // DocumentsChanges.ChangeType.FieldChanged
}