Dapper 多映射两个相同类型的属性

Question

假设我将联系人以扁平形式存储在我的数据库中，这样我就可以像这样查询它们:

SELECT Name, HomeHouseNumber, HomePostcode, WorkHouseNumber, WorkPostcode FROM Contacts

我想在我的 C# 代码中多一点结构，并有一个带有家庭和工作地址的联系人的简单定义。

class Address
{
    public string HouseNumber { get; set; }
    public string Postcode { get; set; }
}

class Contact
{
    public string Name { get; set; }
    public Address HomeAddress { get; set; }
    public Address WorkAddress { get; set; }
}

我发现我可以使用多映射来提取家庭地址，方法是在 select 中为列设置别名，如下所示:

IEnumerable<Contact> GetContacts()
{
    return Connection.Query<Contact, Address, Address, Contact>(
        "SELECT Name, HomeHouseNumber as HouseNumber, HomePostcode as Postcode, WorkHouseNumber, WorkPostcode FROM Contacts",
        (contact, home, work) =>
        {
            contact.HomeAddress = home;
            contact.WorkAddress = work;
            return contact;
        },
        splitOn: "HouseNumber,WorkHouseNumber");
}

但是，我不能以映射它们的方式为工作地址列设置别名。 Dapper 可以为我执行这个映射还是我必须手动执行？

Answer 1

令人难以置信的是，解决方案是为列提供相同的别名。我不认为 SQL 会允许这样做，但确实如此，而且 Dapper 完美地映射了这一切。

IEnumerable<Contact> GetContacts()
{
    return Connection.Query<Contact, Address, Address, Contact>(
        "SELECT Name, HomeHouseNumber as HouseNumber, HomePostcode as Postcode, WorkHouseNumber as HouseNumber, WorkPostcode as Postcode FROM Contacts",
        (contact, home, work) =>
        {
            contact.HomeAddress = home;
            contact.WorkAddress = work;
            return contact;
        },
        splitOn: "HouseNumber,HouseNumber");
}