Voir la source de Mongodb and csharp

[[Category:.NET]]
= Links =
* [https://www.mongodb.com/developer/languages/csharp/using-linq-query-mongodb-dotnet-core-application Using LINQ to Query MongoDB in a .NET Core Application]
* [https://www.mongodb.com/developer/languages/csharp/create-restful-api-dotnet-core-mongodb Create a RESTful API with .NET Core and MongoDB]
* [https://www.mongodb.com/developer/languages/csharp/joining-collections-mongodb-dotnet-core-aggregation-pipeline Joining Collections in MongoDB with .NET Core and an Aggregation Pipeline]
* [https://www.mongodb.com/developer/languages/csharp C# and MongoDB]

= Access to a collection =
<kode lang='cs'>
var mongoClient = new MongoClient("MONGODB_CONNECTION_STRING");
var database = mongoClient.GetDatabase("DB_NAME");
var collection = database.GetCollection<MyClass>("COLLECTION_NAME");
</kode>

= Dependency injection =
<filebox fn='Program.cs'>
builder.Services
    .Configure<MongoConfiguration>(builder.Configuration.GetSection("Mongo"))
    .AddSingleton<IMongoClient>(x =>
        {
            var mongoConfiguration = x.GetRequiredService<IOptions<MongoConfiguration>>().Value;
            var settings = MongoClientSettings.FromConnectionString(mongoConfiguration.ConnectionString);
            settings.LinqProvider = LinqProvider.V3;
            return new MongoClient(settings);
        })
    .AddSingleton(x =>
    {
        var client = x.GetRequiredService<IMongoClient>();
        var configuration = x.GetRequiredService<IOptions<MongoConfiguration>>().Value;
        return client.GetDatabase(configuration.DatabaseName);
    })
    .AddSingleton(x =>
    {
        var database = x.GetRequiredService<IMongoDatabase>();
        return database.GetCollection<MyCollection>(GetConfigurationValue("MyCollectionName"));
    });
</filebox>

<filebox fn='MongoConfiguration.cs' collapsed>
public class MongoConfiguration
{
    public string ConnectionString { get; set; } = string.Empty;

    public string DatabaseName { get; set; } = string.Empty;
}
</filebox>

= Find =
== Filter ==
<kode lang='cs'>
var builder = Builders<MyClass>.Filter;
FilterDefinition<MyClass> filter = builder.Empty;

filter &= builder.Exists(x => x.Property1);
filter &= builder.Eq(x => x.Property1, "id");
filter &= builder.In(x => x.Property1, new[] { "id1", "id2" });  // filter by Property1 equals to one of the ids

var result = await collection.Find(filter).ToListAsync();
var result = (await collection.FindAsync(filter)).ToList();
</kode>

== Handle different types ==
<kode lang='cs'>
// get all the documents
var bsonDocumentCollection = database.GetCollection<BsonDocument>("MyCollection");
var filter = Builders<BsonDocument>.Filter.Empty;
var result = await bsonDocumentCollection.Find(filter).ToListAsync();

// get all the Class1 document
var class1Collection = database.GetCollection<Class1>("MyCollection");
await type1Collection.InsertOneAsync(new Class1 { Name = "Name1" });
var filter = Builders<Class1>.Filter.Eq(x => x.Type, nameof(Class1));
var filter = Builders<SimpleClass>.Filter.Exists(x => x.Name); // get all the documents which have a property Name
var result = await class1Collection.Find(filter).ToListAsync();

class Class1
{
    public ObjectId Id { get; set; }
    public string Name { get; set; } = string.Empty;
    public string Type { get; set; } =  nameof(Class1);
}
</kode>

= Pipeline =
<kode lang='cs'>
var stages = new BsonDocument[]
{
    MatchStage(getTimeSeriesQuery),
    ProjectionStage(),
    SortStage()
};
var pipeline = PipelineDefinition<InputClass, OutputClass>.Create(stages);

var results = (await myCollection.AggregateAsync(pipeline)).List();

BsonDocument MatchStage(GetTimeSeriesQuery getTimeSeriesQuery)
{
    var match = new BsonDocument("property1", "value1");
    if (!string.IsNullOrEmpty(variable2))
    {
        match.AddRange(
            new BsonDocument("property2", variable2)
        );
    }
    return new BsonDocument("$match", match);
}

BsonDocument ProjectionStage() =>
    new BsonDocument(
        "$project",
        new BsonDocument
        {
            { "_id", 0 },
            { "property1", 1 },
            { "property2", 1 }
        }
    );

BsonDocument SortStage() =>
    new BsonDocument("$sort", new BsonDocument("timestamp", 1));
</kode>

= [https://stackoverflow.com/questions/30333925/how-do-i-log-my-queries-in-mongodb-c-sharp-driver-2-0 Log] =
<kode lang='cs'>
var mongoUrl = new MongoUrl("MONGODB_CONNECTION_STRING");
var mongoClientSettings = MongoClientSettings.FromUrl(mongoUrl);
mongoClientSettings.ClusterConfigurator = cb =>
{
    cb.Subscribe<CommandStartedEvent>(e =>
    {
        logger.LogTrace($"{e.CommandName} - {e.Command.ToJson()}");
    });
};
this.mongoClient = new MongoClient(mongoClientSettings);
</kode>
Configure the [[Asp.net_core_7#Log|Log]] so it will be displayed in Visual Studio Output Debug window.
* [https://www.mongodb.com/docs/drivers/csharp/current/fundamentals/logging/#configure-logging Configure logging]

= Serialize a dictionary with an Enum as key =
Error: An error occurred while serializing the Values property of class ...: When using DictionaryRepresentation.Document key values must serialize as strings
<kode lang='cs'>
class MyClass
{
    public ObjectId Id { get; set; }
    public Dictionary<MyEnum, int> Values { get; set; } = [];
}

// serialize the enum as string
BsonSerializer.RegisterSerializer(new EnumSerializer<MyEnum>(BsonType.String));
</kode>