Filter with regex MongoDB C# driver

Question

I am trying to match the fields of originalEmail with a mail address like [email protected], but no matter, case sensitive means to also find [email protected] fields.

public ObjectId? GetEntityIdByOriginalEmail(string originalEmail)
{
    FilterDefinition<Entity> filter = "{ x : { $regex : /" + originalEmail + "//i } }";
    var entity = _entitiesStorage.GetSingleOrDefault(filter);

    if (entity == null)
        return null;

    return entity._id;
}

This didn't work for me. Why?

Answer 1

You can use Builders.Filter.Regex.

public async Task<Entity> GetEntityIdByOriginalEmail(string originalEmail)
{
    var collection = GetCollection();
    var filter = Builders<Entity>.Filter.Regex("x", new BsonRegularExpression(originalEmail, "i"));
    return await collection.Find(filter).FirstOrDefaultAsync();
}