Unable to determine the serialization information for "linq query"-CodePudding

"fullNames" is a list of strings that I want to search for in a database with the 2 tables "FistName" and "LastName". But this code returns the error: "Unable to determine the serialization information for u => (u.FirstName u.LastName)."

var filter = builder.In(u => u.FirstName   u.LastName, fullNames);

var task = _db.GetCollection<Models.User>(Models.CosmosDb.Collections.Users)
                            .Find(filter)
                            .ToListAsync();

var users = await _asyncRetryPolicy.ExecuteAsync(() => task);

Tried to replace the first line with this, but with the same result:

var filter = builder.In(u => $"{u.FirstName}{u.LastName}", fullNames);

What am I doing wrong?

CodePudding user response：

The driver expects a lambda expression that evaluates to a simple property as parameter for In. In the sample, the lambda expression concatenates two properties, hence the error.

Instead of using a Find, you could use Aggregate. This offers more options when querying and reshaping the data.

In this sample, the first stage would be a $set stage that concatenates the first and last name of the document. In a subsequent $match stage, you can include the $in condition and filter the data.

From a performance perspective, it would be best if you store the full name with the documents. Then you only need a simple filter that can also use an index.