CSVHelper：一行，多个类图

Question

我有一行作为多个类的组合。此后，这些类代表一个嵌套的聚合对象。 例如：

(header)product_name、product_sku、product_description、promotion_date、promotion_price

（数据）xxx，1234，“伟大的产品”，202 年 12 月 4 日，3.41 美元

我想读取 Product 对象中的前 3 列，然后将其他两个列读取到 Promotion 对象中。 我可以用两张地图做到这一点吗？我可以在 classMap 中的两个类之间创建视图吗？

Answer 1

你可以用几张地图来做

public class Program
{
    static void Main(string[] args)
    {
        using (var stream = new MemoryStream())
        using (var writer = new StreamWriter(stream))
        using (var reader = new StreamReader(stream))
        using (var csv = new CsvReader(reader, CultureInfo.InvariantCulture))
        {
            writer.WriteLine("product_name,product_sku,product_description,promotion_date,promotion_price");
            writer.WriteLine("xxx,1234,great product,12/4/202,$3.41");
            writer.Flush();
            stream.Position = 0;

            csv.Configuration.RegisterClassMap<TransactionMap>();

            var records = csv.GetRecords<Transaction>().ToList();
        }
    }
}

public class TransactionMap : ClassMap<Transaction>
{
    public TransactionMap()
    {
        References<ProductMap>(m => m.Product);
        References<PromotionMap>(m => m.Promotion);
    }
}

public class ProductMap : ClassMap<Product>
{
    public ProductMap()
    {
        Map(m => m.Name).Name("product_name");
        Map(m => m.Sku).Name("product_sku");
        Map(m => m.Description).Name("product_description");
    }
}

public class PromotionMap : ClassMap<Promotion>
{
    public PromotionMap()
    {
        Map(m => m.Date).Name("promotion_date");
        Map(m => m.Price).Name("promotion_price");
    }
}

public class Transaction
{
    public Product Product { get; set; }
    public Promotion Promotion { get; set; }
}

public class Product
{
    public string Name { get; set; }
    public string Sku { get; set; }
    public string Description { get; set; }
}

public class Promotion
{
    public DateTime Date { get; set; }
    public string Price { get; set; }
}

或者一张地图

public class Program
{
    static void Main(string[] args)
    {
        using (var stream = new MemoryStream())
        using (var writer = new StreamWriter(stream))
        using (var reader = new StreamReader(stream))
        using (var csv = new CsvReader(reader, CultureInfo.InvariantCulture))
        {
            writer.WriteLine("product_name,product_sku,product_description,promotion_date,promotion_price");
            writer.WriteLine("xxx,1234,great product,12/4/202,$3.41");
            writer.Flush();
            stream.Position = 0;

            csv.Configuration.RegisterClassMap<TransactionMap>();

            var records = csv.GetRecords<Transaction>().ToList();
        }
    }
}

public class TransactionMap : ClassMap<Transaction>
{
    public TransactionMap()
    {
        Map(m => m.Product.Name).Name("product_name");
        Map(m => m.Product.Sku).Name("product_sku");
        Map(m => m.Product.Description).Name("product_description");
        Map(m => m.Promotion.Date).Name("promotion_date");
        Map(m => m.Promotion.Price).Name("promotion_price");
    }
}

public class Transaction
{
    public Product Product { get; set; }
    public Promotion Promotion { get; set; }
}

public class Product
{
    public string Name { get; set; }
    public string Sku { get; set; }
    public string Description { get; set; }
}

public class Promotion
{
    public DateTime Date { get; set; }
    public string Price { get; set; }
}