Equivalent for SetUnion in C# driver - mongodb

Question

I have a field in mongodb document which contains an array of numbers. I want to update this field with newly received numbers. But i need to add the numbers only if the number is not present in the array. In MongoDB we can use $setUnion but i am not sure on C# driver side. Anyone please suggest the solution.

Answer 1

$setUnion is Used to produce aggregation output.
You need to use AddToSetEach from c# driver
Please find full code snippet with check after insert
public static void Main()
{
var client = new MongoClient("mongodb://localhost:27017");
var database = client.GetDatabase("test");
var collection = database.GetCollection<KalaimaniData>("kalaimani");
// create array to inser
var arrayToInsert = new[] { 1, 4, 5, 6 };
var arrayToMerge = new[] { 2, 3, 4, 5 };
var arrayExpected = new[] { 1, 4, 5, 6, 2, 3 };
var doc = new KalaimaniData { Numbers = arrayToInsert };
collection.InsertOne(doc);
var filter = Builders<KalaimaniData>.Filter.Eq(x => x.Id, doc.Id);
var updateDef = new UpdateDefinitionBuilder<KalaimaniData>().AddToSetEach(x => x.Numbers, arrayToMerge);
collection.UpdateOne(filter, updateDef);
// retrive and compare
var changed = collection.Find(filter).First();
var matched = 0;
foreach (var element in arrayExpected)
{
if (changed.Numbers.Contains(element))
{
matched++;
}
}
if (changed.Numbers.Length == matched)
{
Console.WriteLine("OK");
}
else
{
Console.WriteLine("NOK");
}
Console.ReadLine();
}
/// <summary>TODO The kalaimani data.</summary>
class KalaimaniData
{
/// <summary>Gets or sets the id.</summary>
public ObjectId Id { get; set; }
/// <summary>Gets or sets the numbers.</summary>
public int[] Numbers { get; set; }
}