Duplicates in Realm for UWP

Question

I have two classes and one of them has a relation to another:

public FirstClass
{
    public string Name {get; set;}
    public string Age {get; set;}
}

and another class where I use this realm object like this for the to-many relationship:

public OtherClass 
{
    public IList<FirstClass> From {get; set;}
    public IList<FirstClass> To {get; set;}
}

my Problem is that for each saving of a new OtherClass the FirstClass is also saved as a new one. But I want that if the same FirstClass is saved that it has a link to the saved one and no duplicate is created. Is that possible? And if yes how?

Answer 1

FirstClass doesn't have a primary key defined, so there's no way for Realm to know that you want an existing instance. You can add a primary key on FirstClass and then do something like:

public FirstClass : RealmObject
{
    [PrimaryKey]
    public int Id { get; set; }

    // Other properties
}

var otherClass = ...;
realm.Write(() =>
{
    realm.Add(otherClass, update: true);
});