Question

我想制作一个MyProduct对象的列表，当我将子对象映射到父对象时问题是

我的代码看起来像这样

  ShopDatabaseEntities db = new ShopDatabaseEntities();
    var Result1 = (from Products in db.Products
                  join ProductProperties in db.ProductProperties on Products.ProductId equals ProductProperties.ProductId
                  join Properties in db.Properties on ProductProperties.PropertyId equals Properties.PropertyId

                  select new
                  {

                      Products.ProductName,
                      Products.ProductPrice,

                      ProductProperties.PropertyValue,
                      Properties.PropertyName,
                      ProductProperties.PropertyId

                  }).ToList();
    List<MyProduct> lii = new List<MyProduct>();
    foreach (var item in Result1)
    {
        MyProduct pp = new MyProduct();
        pp = (from c in Result1
              select new MyProduct { Name = item.ProductName }).First();

        MyProperty e = new MyProperty();
        e.PropertyName = item.PropertyName;
        e.PropertyValue = item.PropertyValue;

        pp.pros.Add(e);
        lii.Add(pp);
    }

Answer 1

在我看来，这更像是你想要的东西：

var query =
    from Products in db.Products
    join ProductProperties in db.ProductProperties on Products.ProductId equals ProductProperties.ProductId
    join Properties in db.Properties on ProductProperties.PropertyId equals Properties.PropertyId
    select new
    {
        ProductProperties.PropertyValue,
        Properties.PropertyName,
        ProductProperties.PropertyId,
        Products.ProductName,
        Products.ProductPrice
    };

List<MyProduct> lii =
    query
        .ToArray()
        .GroupBy(x => new
        {
            x.ProductName,
            x.ProductPrice
        }, x => new
        {
            x.PropertyValue,
            x.PropertyName,
            x.PropertyId
        })
        .Select(x => new MyProduct()
        {
            Name = x.Key.ProductName,
            pros = x
                .Select(y => new MyProperty()
                {
                    PropertyName = y.PropertyName,
                    PropertyValue = y.PropertyValue,
                })
                .ToList()
        })
        .ToList();

顺便说一句，这是您应该在问题中包含的代码，以便更轻松地回答：

public class ShopDatabaseEntities
{
    public List<MyProduct> Products = new List<MyProduct>();
    public List<MyProductProperty> ProductProperties = new List<MyProductProperty>();
    public List<MyProperty> Properties = new List<MyProperty>();
}

public class MyProduct
{
    public int ProductId;
    public string Name;
    public string ProductName;
    public decimal ProductPrice;
    public List<MyProperty> pros = new List<MyProperty>();
}

public class MyProductProperty
{
    public int ProductId;
    public int PropertyId;
    public double PropertyValue;
}

public class MyProperty
{
    public int PropertyId;
    public string PropertyName;
    public double PropertyValue;
}

类型defs非常有帮助。

如何将子对象映射到Linq的父对象

1 个答案: