Index query returning null value

[natesoch]

I can't seem to figure out the cause of a null value been returned from a query on a map index that I created. I have verified that it is created in my db and that the content item I want exists, but I still am lost on what else I should be considering.
The content part I am searching on:

public class Client : ContentPart
{
    public TextField ClientCode { get; set; } = new TextField();
    public BooleanField AzureHosted { get; set; } = new BooleanField();
}

My map index and provider:

public class ClientIndex : MapIndex
{
    /// <summary>
    /// The client code of a client
    /// </summary>
    public string ClientCode { get; set; } = string.Empty;

}

public class ClientIndexProvider : IndexProvider<ContentItem>
{
    public override void Describe(DescribeContext<ContentItem> context)
    {
        context.For<ClientIndex?>().Map(contentItem =>
        {
            Client? productPart = contentItem.As<Client?>();
            return productPart != null
                ? new ClientIndex
                {
                    ClientCode = productPart.ClientCode.Text
                }
                : null;
        });
    }
}

My Migration file:

public class Migrations : DataMigration
{
    private readonly IRecipeMigrator _recipeMigrator;

    public Migrations(IRecipeMigrator recipeMigrator)
    {
        _recipeMigrator = recipeMigrator;
    }
    public async Task<int> CreateAsync()
    {
        
        await _recipeMigrator.ExecuteAsync("ClientRecipe.json", this);
        await _recipeMigrator.ExecuteAsync("AzureAccessFormRecipe.json", this);

        return 1;

    }
    public int UpdateFrom1()
    {
        SchemaBuilder.CreateMapIndexTable<ClientIndex>(table => table
            .Column<string>(nameof(ClientIndex.ClientCode), column => column.NotNull().WithLength(6)));
        return 2;
    }

}

How I am querying:

 public async Task<ContentItem?> GetClientAsync(string ClientCode)
    {
        //doesn't work
        ContentItem test =  await _session.Query<ContentItem, ClientIndex>(index => index.ClientCode == ClientCode).FirstOrDefaultAsync();

I only have 1 content item (for testing) and when I do
await _session.Query<ContentItem, ContentItemIndex>(index => index.ContentType == _contentType).FirstOrDefaultAsync();
I am able to get it, but not when I am trying to query. Does anyone have any insight on this issue?

[jtkech]

Has your ClientIndex table been created? Is your index table populated?

Is your ClientIndexProvider registered in your module startup?

Hmm, I would replace

Client? productPart = contentItem.As<Client?>();

With

var productPart = contentItem.As<Client>();

[natesoch]

Thanks! Changing it to be non-nullable solved the problem. The query now executes like it should.