Help handling null decimal in data

[sgrassie]

Can anyone tell me what I'm doing wrong here? I would expect that the missing values would be replaced with 0 and the decimal type conversion would succeed.

    public record Data(decimal First, decimal Second, decimal Third);
    
    [Fact]
    public void ShouldHandleNullDecimals()
    {
        var csvData = """
                      First,Second,Third
                      1.0,,
                      """;
        
        using var memoryStream = new MemoryStream(Encoding.UTF8.GetBytes(csvData));
        using var reader = new StreamReader(memoryStream);
        using var csv = new CsvReader(reader, new CsvConfiguration(CultureInfo.InvariantCulture));
        csv.Context.TypeConverterOptionsCache.GetOptions<decimal>().NullValues.Add("0");
        
        var data = csv.GetRecords<Data>().ToList().First();

        data.First.Should().Be(1.0m);
        data.Second.Should().Be(0m);
        data.Third.Should().Be(0m);
    }

Instead I get

CsvHelper.TypeConversion.TypeConverterException
The conversion cannot be performed.
    Text: ''
    MemberName: 
    MemberType: 
    TypeConverter: 'CsvHelper.TypeConversion.DecimalConverter'
IReader state:
   ColumnCount: 3
   CurrentIndex: 1
   HeaderRecord:
["First","Second","Third"]
IParser state:
   ByteCount: 0
   CharCount: 24
   Row: 2
   RawRow: 2
   Count: 3
   RawRecord:
1.0,,

   at CsvHelper.TypeConversion.DefaultTypeConverter.ConvertFromString(String text, IReaderRow row, MemberMapData memberMapData)

Am I not doing this in the right way?

[JoshClose]

NullValues are data that is converted to null. What you're doing would set null if the field was 0.

Your properties in Record aren't Nullable, so you don't want null anyway.

You can set a default of 0.

public record Data([Default(0)]decimal First, [Default(0)]decimal Second, [Default(0)]decimal Third);

[sgrassie]

Thanks. That is stupidly obvious now that I can see it 🤣