Creating and Modifying Counters

• Use the CountersFor.Increment method to create a new Counter or modify an existing Counter's value.

• If the Counter exists, Increment will add a number to the Counter's current value.
  If the Counter doesn't exist, Increment will create it and set its initial value.

• In this page:

  • Increment Syntax
  • Increment Usage
  • Code Sample

Increment Syntax

void Increment(string counterName, long incrementValue = 1);

Parameters	Type	Description
counterName	string	Counter's name
incrementValue	long	Increase Counter by this value. Default value is 1. For a new Counter, this will be its initial value.

Increment Usage

• Flow:

• Open a session
• Create an instance of CountersFor.
  • Either pass CountersFor an explicit document ID, -or-
  • Pass it an entity tracked by the session, e.g. a document object returned from session.query or from session.Load.
• Execute CountersFor.Increment
• Execute session.SaveChanges for the changes to take effect

• Note:
  • Modifying a Counter using Increment only takes effect when session.SaveChanges() is executed.
  • To decrease a Counter's value, pass the method a negative number to Increment.

Code Sample

// 1. Open a session
using (var session = docStore.OpenSession())
{
  // 2. pass CountersFor's constructor a document ID  
  var documentCounters = session.CountersFor("products/1-C");

  // 3. Use `CountersFor.Increment`
  documentCounters.Increment("ProductLikes"); // Increase "ProductLikes" by 1, or create it with a value of 1
  documentCounters.Increment("ProductDislikes", 1); // Increase "ProductDislikes" by 1, or create it with a value of 1
  documentCounters.Increment("ProductPageViews", 15); // Increase "ProductPageViews" by 15, or create it with a value of 15
  documentCounters.Increment("DaysLeftForSale", -10); // Decrease "DaysLeftForSale" by 10, or create it with a value of -10

  // 4. Save changes to the session
  session.SaveChanges();
}