[MongoDB .NET Driver] UpdateOneAsync & UpdateManyAsync sample ref: http://qiita.com/SHUAI/items/fc154ce42d6944bcedfe

file0.cs

var filter = Builders<Member>.Filter.Eq<string>(m => m.PersonId, id);
var update = Builders<Member>.Update.Set(m => m.Phone, phone);
var result = db.GetCollection<Member>(colName).UpdateOneAsync(filter, update).ConfigureAwait(continueOnCapturedContext: false);

file1.cs

var filter = Builders<Member>.Filter.In<string>(m => m.PersonId, ids);
var update = Builders<Member>.Update.Set(m => m.ZipCode, zipCode);
var result = db.GetCollection<Member>(colName).UpdateManyAsync(filter, update).ConfigureAwait(continueOnCapturedContext: false);
if (result.IsModifiedCountAvailable)
{
    // result.ModifiedCount: 取得更新筆數
}