无法隐式转换类型'System.Collections.Generic.IEnumerable [重复]

Question

我需要使用(Where(x=>x.IsMallExternal == false)) 过滤 ObservableCollection。

使用此代码：

ObservableCollection<Shop> test = allShopsForCat.Where(x => x.IsMallExternal == false);

我收到此错误：

Cannot implicitly convert type 'System.Collections.Generic.IEnumerable<DataModel.Shop>' to 'System.Collections.ObjectModel.ObservableCollection<DataModel.Shop>'. 

所以我改用这段代码作为解决方案，但似乎不是最好的方法。

• 我想知道如何在我的方法中使用.Where 过滤 ObservableCollection。

---

   public ObservableCollection<Shop> Shops
        {
            get
            {
                ObservableCollection<Shop> allShopsForCat = App._dataSource.GetShopsForCategoryAll(_id);

                //ObservableCollection<Shop> test = allShopsForCat.Where(x => x.IsMallExternal == false); // THIS DOES NOT WORK
                ObservableCollection<Shop> shopsNotExternal = new ObservableCollection<Shop>();
                // Get only shops for category which are internal to mall
                foreach (var shop in allShopsForCat)
                {
                    if (shop.IsMallExternal == false)
                    {
                        shopsNotExternal.Add(shop);
                    }
                }
                return shopsNotExternal;
            }
        }

Answer 1

所有 linq 查询都返回 IEnumerable（或一些派生的变体，例如 IOrderedEnumerable），因此您只需将其转换为列表

var filtered = allShopsForCat.Where(x => x.IsMallExternal == false);
ObservableCollection<Shop> shopsNotExternal = new ObservableCollection<Shop>(filtered);

更新

这项工作很好：

List<int> temp = new List<int> { 1, 3, 5, 5, 6, 7, 7, 8 };

var filtered = temp.Where(i => i == 5 || i == 7);
ObservableCollection<int> l = new ObservableCollection<int>(filtered);