扩展方法中的两个泛型类型
本文关键字:两个 泛型类型 方法 扩展 | 更新日期: 2023-09-27 18:36:51
现在我的代码是这样的代码:(简化!
public static IQueryable<T> ListedProducts<T,V>(this IQueryable<T> collection)
where T : ProductCollection<V>
where V: Product
{
return collection.Where(x => x.Listed == true);
}
要使用它,我必须像这样定义这两种类型:
SomeCollection.ListedProducts<BikeCollection,BikeProduct>()
这就是我希望它的样子:
我希望能够写一些东西 lkie 这个:
public static IQueryable<T> ListedProducts<T<V>>(this IQueryable<T<V>> collection)
where T : ProductCollection<V>
{
return collection.Where(x => x.Listed == true);
}
我只需要写的地方:
SomeCollection.ListedProducts()
我认为这是可能的,因为"SomeCollection"包含通用ListedProducts方法的两种类型。
希望我的问题足够清楚,并且有一个解决方案:)
更新
关于我的代码是如何设置的,似乎有很多疑问,所以这里有一些类(简化)
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public class ProductCollection<T> where T : Product
{
public int Id { get; set; }
public string CollectionName { get; set; }
public virtual ICollection<T> Products { get; set; }
public bool Listed { get; set; }
}
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public class BikeCollection : ProductCollection<BikeProduct>
{
//Bike specific properties
}
编辑:根据您最近的更新,我建议如下:
建议:更改ProductCollection<T>
,使其实现IEnumerable<T>
:
public class ProductCollection<T> : IEnumerable<T>
where T : Product
{
public int Id { get; set; }
public string CollectionName { get; set; }
public virtual ICollection<T> Products { get; set; }
public bool Listed { get; set; }
// This is all it takes to implement IEnumerable<T>
public IEnumerator<T> GetEnumerator() { return this.Products.GetEnumerator(); }
IEnumerator IEnumerable.GetEnumerator() { return this.Products.GetEnumerator(); }
}
然后,可以通过以下方式更改扩展:
public static IEnumerable<T> ListedProducts<T>(this IEnumerable<T> collection)
where T : Product
{
return collection.Where(x => x.Listed == true);
}
这允许您执行以下操作:
// WHERE BikeCollection : ProductCollection<BikeProduct>
// AND BikeProduct : Product
var someCollection = new BikeCollection();
// What you want
var listedBikes1 = someCollection.ListedProducts();
// Another way you can do it, if ProductCollection<T> : IEnumerable<T>
var listedBikes2 =
from product in someCollection
where product.Listed
select product;
这项工作是谁的?
public static class StaticFunctions
{
public static IQueryable<ProductCollection<T>> ListedProducts<T>(this IQueryable<ProductCollection<T>> collection)
where T : Product
{
return collection.Where(x => x.Listed == true);
}
}
public class ProductCollection<T>
where T:Product
{
public int Id { get; set; }
public string CollectionName { get; set; }
public virtual ICollection<T> Products { get; set; }
public bool Listed { get; set; }
}
public class BikeCollection : ProductCollection<BikeProduct>
{
//Bike specific collection
}
public class BikeProduct:Product
{
//Can be anything
}
public class Product
{
//Can be anything
}
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
IQueryable<ProductCollection<BikeProduct>> titi = new EnumerableQuery<ProductCollection<BikeProduct>>(new List<ProductCollection<BikeProduct>>());
titi.ListedProducts();
var toto = 1;
}
}