Support translating value objects that are using a converter

[adampaquette]

Context

We are using immutable value objects that wraps primitives with validations in our entities.

A value object (VO) could be represented as the following:

public record CustomerName
{
    public string Value { get; }

    public CustomerName(string value)
    {
        if (string.IsNullOrWhiteSpace(value))
        {
            throw new ValidationException("CustomerName can't be empty.");
        }

        value = Normalize(value);

        if (value.Length > 100)
        {
            throw new ValidationException("CustomerName exceeds the maximum length of 100 characters.");
        }

        Value = value;
    }

    public static CustomerName From(string value)
        => new(value);

    public string Normalize(string value)
        => CultureInfo.CurrentCulture.TextInfo.ToTitleCase(value).Trim();
}

99% of our VO are Domain Primitives, they only contain a single property and we don't want to treat them as complex objects, so we use converters in the configuration:

cb.Property(c => c.Name).HasConversion(name => name.Value, s => CustomerName.From(s));

Actual use

To make a search query translate to Sql, we need to cast the VO as a string because the underlying property Value does not exist in the database and sometimes we have to cast as object before casting as string.

db.Customers.Where(c => ((string)c.FirstName).Contains(firstName.Value)));

Expected use

We would like to be able to access the underlying property in the query as valid C# code and still generate the correct Sql.

db.Customers.Where(c => c.FirstName.Value.Contains(firstName.Value)));

I've made a test case here: adampaquette#1
I would need guidance on how to achieve this.
Thank you

[roji]

Duplicate of #10434