MongoDB and C#: Case insensitive search

Question

I am using MongoDB and the C# driver for MongoDB.

I recently discovered that all queries in MongoDB are case-sensitive. How can I make a case-insensitive search?

I found one way to do this:

Query.Matches(
    "FirstName", 
    BsonRegularExpression.Create(new Regex(searchKey,RegexOptions.IgnoreCase)));

Answer 1

The simplest and safest way to do that is using Linq:

var names = namesCollection.AsQueryable().Where(name =>
    name.FirstName.ToLower().Contains("hamster"));

As explained in the tutorial ToLower, ToLowerInvariant, ToUpper and ToUpperInvariant all perform matches in a case insensitive way. After that you can use all the supported string methods like Contains or StartsWith.

This example will generate:

{
    "FirstName" : /hamster/is
}

The i option makes it case insensitive.