Update Data - .NET SDK
September 23, 2025 ยท View on GitHub
Updates are the same as creating a new document. When updating documents, all writes must happen in a transaction.
Modify an Object
The following example shows how to modify an existing object. In this example,
we are updating the Name and Age properties of a Dog object:
var dog = realm.All<Dog>().First();
realm.WriteAsync(() =>
{
dog.Name = "Wolfie";
dog.Age += 1;
});
Upserts
An upsert allows you to create or modify a document without knowing if the document already exists. For more information, see Upsert a Realm Object.
Update a Collection
The following code demonstrates how to update a collection.
realm.Write(() =>
{
// Create someone to take care of some dogs.
var ali = new Person { Id = id, Name = "Ali" };
realm.Add(ali);
// Find dogs younger than 2.
var puppies = realm.All<Dog>().Where(dog => dog.Age < 2);
// Loop through one by one to update.
foreach (var puppy in puppies)
{
// Add Ali to the list of Owners for each puppy
puppy.Owners.Add(ali);
}
});
NOTE: Because realm uses implicit inverse relationships between the Dog's
Ownersproperty and the Person'sDogsproperty, Realm automatically updates Ali's list of dogs at the same time we update each dog'sOwnerslist.