Question

我正在实施我的第一个Dapper.Net项目。现在我想知道什么是初始化包含另一个对象的对象的最简单方法（多映射）。

这是我的代码：

public static IEnumerable<ShopPrefix> GetShopPrefixes(short fiSL)
{
    using (var con = new SqlConnection(Properties.Settings.Default.RM2Con))
    {
        const String sql = @"
            SELECT  locShopPrefix.idShopPrefix,
                    locShopPrefix.fiSL,
                    locShopPrefix.fiShop,
                    locShopPrefix.Prefix,
                    locShopPrefix.Active,
                    locShop.idShop,
                    locShop.ShopName,
                    locShop.ContactPerson,
                    locShop.Street,
                    locShop.ZIP,
                    locShop.City,
                    locShop.Telephone,
                    locShop.Telefax,
                    locShop.Email,
                    locShop.ShopKey
            FROM    locShopPrefix
                    INNER JOIN locShop
                        ON locShopPrefix.fiShop = locShop.idShop
            WHERE   (locShopPrefix.fiSL = @fiSL);";
        con.Open();
        IEnumerable<Tuple<ShopPrefix,Shop>> shops =
            con.Query<ShopPrefix, Shop, Tuple<ShopPrefix, Shop>>(
            sql
            , (shopPrefix, shop) => Tuple.Create(shopPrefix, shop)
            , new { fiSL = fiSL }, splitOn: "idShop"
        );
        foreach (var shop in shops)
            shop.Item1.Shop = shop.Item2;
        return shops.Select(t => t.Item1);
    }
}

所以每个shopPrefix都属于（有）Shop。

问：这是映射两个对象的正确方法，因为Tuple方法使用以下foreach来初始化属性Shop看起来很麻烦吗？

Answer 1

对于简单的一对一对象关系，我认为您不需要IEnumerable<Tuple<>>。以下代码段也应该足够了。

var shopsPrefixes = con.Query<ShopPrefix, Shop, ShopPrefix>(sql
    , (shopPrefix, shop) =>
    {
        shopPrefix.Shop = shop;
        return shopPrefix;
    }
    , new { fiSL = fiSL }
    , splitOn: "idShop"
);
return shopsPrefixes;

dapper.net中的多映射

1 个答案: