c# - Distinct() 返回 List<> 返回重复项

Question

我有一个传递到 Web 服务的过滤器列表，我遍历集合并执行 Linq 查询，然后添加到产品列表，但是当我执行 GroupBy 时和 Distinct()它不会删除重复项。我正在使用 IEnumerable因为当你使用 Disinct它将它转换为 IEnumerable .如果你知道如何更好地构造它并使我的函数返回一种类型 List<Product>将不胜感激。

这是我在 C# 中的代码:

if (Tab == "All-Items")
{
    List<Product> temp = new List<Product>();
    List<Product> Products2 = new List<Product>();
    foreach (Filter filter in Filters)
    {                        
        List<Product> products = (from p in db.Products where p.Discontinued == false
                                  && p.DepartmentId == qDepartment.Id
                                  join f in db.Filters on p.Id equals f.ProductId
                                  join x in db.ProductImages on p.Id equals x.ProductId
                                  where x.Dimension == "180X180"
                                  && f.Name == filter.Name /*Filter*/
                                  select new Product
                                  {
                                      Id = p.Id,
                                      Title = p.Title,
                                      ShortDescription = p.ShortDescription,
                                      Brand = p.Brand,
                                      Model = p.Model,
                                      Image = x.Path,
                                      FriendlyUrl = p.FriendlyUrl,
                                      SellPrice = p.SellPrice,
                                      DiscountPercentage = p.DiscountPercentage,
                                      Votes = p.Votes,
                                      TotalRating = p.TotalRating
                                  }).ToList<Product>();

        foreach (Product p in products)
        {
            temp.Add(p);
        }                        

        IEnumerable temp2 = temp.GroupBy(x => x.Id).Distinct();
        IEnumerator e = temp.GetEnumerator();
        while (e.MoveNext()) {
            Product c = e.Current as Product;
            Products2.Add(c);
        }
    }
    pf.Products = Products2;// return type must be List<Product>                
}

Answer 1

您需要覆盖 Equals 和 GetHashCode 以按值比较 Product。