C# 乐：

即：

---

…但在某些情况下，我可能不想填充

phototegory

对象…-在这些情况下，您当然可以始终创建虚拟的

phototegory

对象，只需设置它们的

Id

。当我只需要传递标识符，但我的方法需要对象实例时，我通常会这样做。为什么不在Dapper的GitHub repo上提出一个问题呢？更有可能的是，您会更快地得到服务，项目所有者的问题也会被记录下来。因为这似乎很普遍。我自己的表通常与相同的列名相关。可能是Hi Sam的重复。这是个好消息，谢谢。此更新版本何时显示在屏幕上？我现在在那里看不到吗？谢谢山姆，一切都解决了：）就像我当时想的那样。谢谢你的修复。

PhotoId (PK - int)  
CategoryId (FK - smallint)  
UserId (int)

CategoryId (PK - smallint)  
CategoryName (nvarchar(50))

public class Photo
{
    public int PhotoId { get; set; }
    public short CategoryId { get; set; }
    public int UserId { get; set; }
    public PhotoCategory PhotoCategory { get; set; }
}

public class PhotoCategory
{
    public short CategoryId { get; set; }
    public string CategoryName { get; set; }
{

var sql = @"select p.*, c.* from Photos p inner 
            join PhotoCategories c 
            on p.CategoryID = c.CategoryID where p.PhotoID = @pid";

cn.Open();
var myPhoto = cn.Query<Photo, PhotoCategory, Photo>(sql, 
               (photo, photoCategory) => { photo.PhotoCategory = photoCategory; 
                                           return photo; }, 
               new { pid = photoID }, null, true, splitOn: "CategoryID").Single();

class Program
{
    static void Main(string[] args)
    {
        var createSql = @"
            create table #Users (UserId int, Name varchar(20))
            create table #Posts (Id int, OwnerId int, Content varchar(20))

            insert #Users values(99, 'Sam')
            insert #Users values(2, 'I am')

            insert #Posts values(1, 99, 'Sams Post1')
            insert #Posts values(2, 99, 'Sams Post2')
            insert #Posts values(3, null, 'no ones post')
        ";

        var sql =
        @"select * from #Posts p 
        left join #Users u on u.UserId = p.OwnerId 
        Order by p.Id";

        using (var connection = new SqlConnection(@"CONNECTION STRING HERE"))
        {
            connection.Open();
            connection.Execute(createSql);

            var data = connection.Query<Post, User, Post>(sql, (post, user) => { post.Owner = user; return post; }, splitOn: "UserId");
            var apost = data.First();

            apost.Content = apost.Content;
            connection.Execute("drop table #Users drop table #Posts");
        }
    }
}

class User
{
    public int UserId { get; set; }
    public string Name { get; set; }
}
class Post
{
    public int Id { get; set; }
    public int OwnerId { get; set; }
    public User Owner { get; set; }
    public string Content { get; set; }
}

class Program
{
    static void Main(string[] args)
    {
        var createSql = @"
            create table #Users (UserId int, Name varchar(20))
            create table #Posts (Id int, UserId int, Content varchar(20))

            insert #Users values(99, 'Sam')
            insert #Users values(2, 'I am')

            insert #Posts values(1, 99, 'Sams Post1')
            insert #Posts values(2, 99, 'Sams Post2')
            insert #Posts values(3, null, 'no ones post')
        ";

        var sql =
        @"select * from #Posts p 
        left join #Users u on u.UserId = p.UserId 
        Order by p.Id";

        using (var connection = new SqlConnection(@"CONNECTION STRING HERE"))
        {
            connection.Open();
            connection.Execute(createSql);

            var data = connection.Query<Post, User, Post>(sql, (post, user) => { post.Owner = user; return post; }, splitOn: "UserId");
            var apost = data.First();

            apost.Content = apost.Content;
            connection.Execute("drop table #Users drop table #Posts");
        }
    }
}

class User
{
    public int UserId { get; set; }
    public string Name { get; set; }
}
class Post
{
    public int Id { get; set; }
    public int UserId { get; set; }
    public User Owner { get; set; }
    public string Content { get; set; }
}

    class Foo1 
    {
        public int Id;
        public int BarId { get; set; }
    }

    class Bar1
    {
        public int BarId;
        public string Name { get; set; }
    }

    public void TestMultiMapperIsNotConfusedWithUnorderedCols()
    {

        var result = connection.Query<Foo1,Bar1,
                      Tuple<Foo1,Bar1>>(
                         "select 1 as Id, 2 as BarId, 3 as BarId, 'a' as Name",
                         (f,b) => Tuple.Create(f,b), splitOn: "BarId")
                         .First();

        result.Item1.Id.IsEqualTo(1);
        result.Item1.BarId.IsEqualTo(2);
        result.Item2.BarId.IsEqualTo(3);
        result.Item2.Name.IsEqualTo("a");

    }

classes: A{Id,FooId} B{FooId,Name} splitOn: "FooId" data: Id, FooId, FooId, Name

SELECT
    user.Name, user.Email, user.AddressId As id, address.*
FROM 
    User user
    Join Address address
    ON user.AddressId = address.AddressId