Question

I would like to connect to the database specified in the connection string, without specifying it again in GetDatabase.

For example, if I have a connection string like this;

mongodb://localhost/mydb

I would like to be able to db.GetCollection("mycollection") from mydb.

This would allow the database name to be configured easily in the app.config file.

Answer 1

Update:

MongoServer.Create is obsolete now (thanks to @aknuds1). Instead this use following code:

var _server = new MongoClient(connectionString).GetServer();

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It’s easy. You should first take database name from connection string and then get database by name. Complete example:

var connectionString = "mongodb://localhost:27020/mydb";

//take database name from connection string
var _databaseName = MongoUrl.Create(connectionString).DatabaseName;
var _server = MongoServer.Create(connectionString);

//and then get database by database name:
_server.GetDatabase(_databaseName);

Important: If your database and auth database are different, you can add a authSource= query parameter to specify a different auth database. (thank you to @chrisdrobison)

From docs:

NOTE If you are using the database segment as the initial database to
use, but the username and password specified are defined in a
different database, you can use the authSource option to specify the
database in which the credential is defined. For example,
mongodb://user:pass@hostname/db1?authSource=userDb would authenticate
the credential against the userDb database instead of db1.