---
lang: ja-jp
breaks: true
---
# CsvHelper で 項目名とプロパティ名が異なる場合のマッピング 2022-11-18

public class OrdersRecordClassMap:
    ClassMap<OrdersRecord>
{
    public OrdersRecordClassMap()
        : base()
    {
        Map(m => m.Name )./* Index(0). */ Name("Name");
        Map(m => m.Email)./* Index(1). */ Name("Email");
    }
}

private async IAsyncEnumerable<T> GetCsvRecordAsync<T, TMap>(
    StorageFile csvFile,
    Encoding? enc = null,
    bool? detectEncodingFromByteOrderMarks = null
    )
    where TMap : ClassMap
{
    // .NET Core では、「Encoding.RegisterProvider」を呼び出す必要がある。
    Encoding.RegisterProvider(CodePagesEncodingProvider.Instance);
    if (enc == null)
    {
        enc = Encoding.UTF8;
    }

    if (detectEncodingFromByteOrderMarks == null)
    {
        detectEncodingFromByteOrderMarks = true;
    }

    using (
        var reader = new StreamReader(
            csvFile.Path,
            enc,
            detectEncodingFromByteOrderMarks.Value
            )
        )
    {
        var configuration = new CsvConfiguration(
            CultureInfo.CurrentCulture
            );
        configuration.Encoding = enc;
        configuration.HasHeaderRecord = true;

        configuration.IncludePrivateMembers = true;

        using (CsvReader csv = new CsvReader(reader, configuration))
        {
            if (typeof(TMap) != typeof(ClassMap))
            {
                csv.Context.RegisterClassMap<TMap>();
            }

            await foreach (T record in csv.GetRecordsAsync<T>()
                        .ConfigureAwait(false)
                )
            {
                yield return record;
            }
        }
    }
}

###### tags: `CsvHelper` `ClassMap`