Xamarin失败中的Firebase查询

Question

我的查询返回一个FirebaseObjects列表：

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

但我想这么做：

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

我是否可以更改我的查询以使其工作，或者这就是它的工作方式？我的意思是，我总是返回一个列表，还是可以直接反序列化到我的Product？

json全结构

    {
  "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

我找到了一个对我有用的解决方案。

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

但我发现了apineda的解决方案。该查询工作正常，但当我尝试使用该产品时会抛出一个异常。

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

但是我想我需要打x# firebase调用才能得到所有，而我的解决方案则是在一个调用中获得所有产品。

Answer 2

查询返回对象列表，因为在查询主节点时不添加任何筛选器。这和说的“一样”

SELECT * FROM PRODUCT;

在一个相关数据库中。

你做不到

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

当您有从请求开始的产品列表时。如果您只想选择一个，那么您需要按键、子键或值进行筛选。

但你可以做：

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

您将拥有一组产品，已经为您反序列化了。

用这个：

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

若要获得单个产品，请将productId定义为节点的密钥。

移动结构到原来的岗位..。