RealmInteger - .NET SDK

Overview

Realm offers RealmInteger as a special integer type you can use as a logical counter. RealmInteger<T> exposes an additional API that can more clearly express intent and generate better conflict resolution steps when using Synchronized Realms. The type argument <T> can be of type byte, short, int, or long. The following example shows how to use a RealmInteger property that maps to an int:

public partial class MyRealmClass : IRealmObject
{
    [PrimaryKey]
    public int _id { get; set; }
    public RealmInteger<int> Counter { get; set; }
}

Implementing a Counter

Traditionally, you would implement a counter by reading a value, incrementing it, and then setting it (myObject.Counter += 1). This does not work well in an asynchronous situation like when two clients are offline. Consider the following scenario:

• The realm object has a counter property of type int. It is currently set to a value of 10.

• Clients 1 and 2 both read the counter property (10) and each increments the value by 1.

• When each client regains connectivity and merges their changes, they expect a value of 11, and there is no conflict. However, the counter value should be 12!

When using a RealmInteger, however, you can call the Increment() and Decrement() methods, and to reset the counter, you set it to 0, just as you would an int:

var myObject = realm.Find<MyRealmClass>(id);
// myObject.Counter == 0
realm.Write(() =>
{
    // Increment the value of the RealmInteger
    myObject.Counter.Increment(); // 1
    myObject.Counter.Increment(5); // 6
    // Decrement the value of the RealmInteger
    // Note the use of Increment with a negative number
    myObject.Counter.Decrement(); // 5
    myObject.Counter.Increment(-3); // 2
    // Reset the RealmInteger
    myObject.Counter = 0;
    // RealmInteger<T> is implicitly convertable to T:
    int bar = myObject.Counter;
});

A RealmInteger is backed by traditional integer type, so no schema migration is required when changing a property type from T to RealmInteger<T>.