在Xamarin火力地堡查询失败

Question

我的查询返回FirebaseObjects列表：

IReadOnlyCollection<Firebase.Xamarin.Database.FirebaseObject<object>> items = await firebase.Child("product").OnceAsync<object>(); 

但我想这样做：

Product product = await firebase.Child("product").OnceAsync<Product>(); 

我可以改变我的查询，使其工作，或者是这个它是如何工作的？ 我的意思是，我将总是找回列表，还是可以直接反序列化到我的Product对象？

JSON的完整结构

{ 
    "product1": { 
    "pname": "Peppermint Kiss", 
    "teaType": "Black Tea", 
    "company": "PersnickeTea", 
    "packSize": { 
     "teabag": [ 
     { 
      "qty": 1, 
      "price": 1.5, 
      "tImage": "singleCup.jpg" 
     }, 
     { 
      "qty": 5, 
      "tinPrice": 6.95, 
      "tImage": "blackTeaTin.jpg" 
     }, 
     { 
      "qty": 8, 
      "price": 10, 
      "tImage": "blackTeabox.jpg" 
     }, 
     { 
      "qty": 12, 
      "boxPrice": 14.95, 
      "tImage": "trayBox.jpg" 
     } 
     ], 
     "looseLeaf": [ 
     { 
      "qty": 46, 
      "price": 7.95, 
      "tImage": "mintKissPak.jpg" 
     } 
     ] 
    }, 
    "ingredients": [ 
     "black tea", 
     "peppermint leaves", 
     "candy pieces", 
     "organic peppermint oil", 
     "natural creme flavor", 
     "raspberry leaves", 
     "red clover", 
     "anise seed" 
    ], 
    "prepMethod": [ 
     "infuser", 
     "teabags", 
     "strainer", 
     "iced" 
    ] 
    }, 
    "product2": { 
    "pname": "Spearmint Kiss", 
    "teaType": "Black Tea", 
    "company": "PersnickeTea", 
    "packSize": { 
     "teabag": [ 
     { 
      "qty": 1, 
      "price": 1.5, 
      "tImage": "singleCup.jpg" 
     }, 
     { 
      "qty": 5, 
      "tinPrice": 6.95, 
      "tImage": "blackTeaTin.jpg" 
     }, 
     { 
      "qty": 8, 
      "price": 10, 
      "tImage": "blackTeabox.jpg" 
     }, 
     { 
      "qty": 12, 
      "boxPrice": 14.95, 
      "tImage": "trayBox.jpg" 
     } 
     ], 
     "looseLeaf": [ 
     { 
      "qty": 46, 
      "price": 7.95, 
      "tImage": "mintKissPak.jpg" 
     } 
     ] 
    }, 
    "ingredients": [ 
     "black tea", 
     "peppermint leaves", 
     "candy pieces", 
     "organic peppermint oil", 
     "natural creme flavor", 
     "raspberry leaves", 
     "red clover", 
     "anise seed" 
    ], 
    "prepMethod": [ 
     "infuser", 
     "teabags", 
     "strainer", 
     "iced" 
    ] 
    }, 
    "product3": { 
    "pname": "Mintymint Kiss", 
    "teaType": "Black Tea", 
    "company": "PersnickeTea", 
    "packSize": { 
     "teabag": [ 
     { 
      "qty": 1, 
      "price": 1.5, 
      "tImage": "singleCup.jpg" 
     }, 
     { 
      "qty": 5, 
      "tinPrice": 6.95, 
      "tImage": "blackTeaTin.jpg" 
     }, 
     { 
      "qty": 8, 
      "price": 10, 
      "tImage": "blackTeabox.jpg" 
     }, 
     { 
      "qty": 12, 
      "boxPrice": 14.95, 
      "tImage": "trayBox.jpg" 
     } 
     ], 
     "looseLeaf": [ 
     { 
      "qty": 46, 
      "price": 7.95, 
      "tImage": "mintKissPak.jpg" 
     } 
     ] 
    }, 
    "ingredients": [ 
     "black tea", 
     "peppermint leaves", 
     "candy pieces", 
     "organic peppermint oil", 
     "natural creme flavor", 
     "raspberry leaves", 
     "red clover", 
     "anise seed" 
    ], 
    "prepMethod": [ 
     "infuser", 
     "teabags", 
     "strainer", 
     "iced" 
    ] 
    } 
} 

Answer 1

我能找到适合我的解决方案。

var items = await firebase.Child("products").OnceAsync<object>(); 
foreach(var item in items) { 
    product = Newtonsoft.Json.JsonConvert.DeserializeObject<Product>.(item.Object.ToString()); 
} 

但我碰上了apineda的解决方案。查询起作用，但在尝试使用产品时引发异常。

var product = await firebase 
      .Child("products") 
      .Child("product1") 
      .OnceAsync<Product>(); 

但我想我会需要做X＃火力呼吁让所有，而我的解决方案得到所有产品的一个电话。

Answer 2

你的查询，因为您所查询的主节点，不添加任何过滤器返回的对象的列表。这与“说话相同”

SELECT * FROM PRODUCT; 

在相关数据库中。

你不能这样做

Product product = await firebase.Child("product").OnceAsync<Product>(); 

当你的产品从正在添加的请求的列表。如果你只想选择一个，那么你需要按键，按键或按值过滤。

但是你可以做，虽然：

var products = await firebase.Child("product").OnceAsync<Product>(); 

，你将有产品的集合，已经反序列化的为您服务。

使用此：

var product = await firebase 
      .Child("product") 
      .Child("your-product-id") 
      .OnceAsync<Product>(); 

为了得到一个单一的产品，如果你确定你的productId是你节点的关键。

将结构移动到原始帖子....