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>();

我可以更改我的查询以使其正常工作，还是这就是它的工作原理？我的意思是，我是否总能找回一个列表，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

您的查询返回对象列表，因为您在不添加任何过滤器的情况下查询主节点。那是＆＃34;同样的＆＃34;如上所述

SELECT * FROM PRODUCT;

在一个临时数据库中。

你做不到

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

当您有来自请求的产品列表时。如果您只想选择一个，则需要按键，子项或值进行过滤。

但你可以这样做：

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

您将拥有一系列已经反序列化的产品。

使用此：

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

如果您将productId定义为节点的关键，则获取单个产品。

将结构移动到原始帖子....

Answer 2

我能够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());
}

但我提出了apineda的解决方案。该查询有效但在我尝试使用该产品时会抛出异常。

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

但我认为我需要进行x＃firebase调用以获取所有产品，而我的解决方案可以在一次调用中获取所有产品。

Xamarin中的Firebase查询失败

2 个答案: