string connectionString = "mongodb://localhost:27017";
MongoServer mongo = MongoServer.Create(connectionString);
mongo.Connect(); //*******here i am getting error.
MongoDatabase database = mongo.GetDatabase("MyDB");
MongoCollection MyData = database.GetCollection<BsonDocument>("users");
BsonDocument Data = new BsonDocument {

};

MyData.Insert(Data);
button1.Text = "Data Inserted";
mongo.Disconnect();