我尝试使用 C# MVC Web 应用程序显示来自 Azure Cosmos DB 的数据(JSON 数据)。 Json数据嵌套如下。我想使用 C# MVC 将 Entries 数组中的信息显示为表格。我无法显示数据。
我正在尝试显示来自 Azure Cosmos DB 的数据(JSON 数据)。我检查了一些在线帖子，但他们直接使用 Json 数据而不是 Azure Jason。 Json数据嵌套如下。我想在 Entries 数组中显示信息 ("dateTime": "2019-07-04T00:00:00", "precisCode": "阵雨", “分钟”:10， "max": 19) 作为使用 c# MVC 的表。我是 azure 和 c# mvc 的新手，我无法显示数据。 请检查下面的代码并让我知道出了什么问题以及可以做什么。
Json 数据:
"id": "302620190704",
"LocationId": "3026",
"CreatedAt": "2019-07-04T21:42:53",
"DateTime": "2019-07-04T00:00:00",
"Entries": {
"0": {
"dateTime": "2019-07-04T00:00:00",
"precisCode": "showers-rain",
"min": 10,
"max": 19
}
},
"_rid": "sklTAKvKt1MBAAAAAAAAAA==",
"_self": "dbs/sklTAA==/colls/sklTAKvKt1M=/docs/sklTAKvKt1MBAAAAAAAAAA==/",
"_etag": "\"020002c6-0000-1a00-0000-5d1e906d0000\"",
"_attachments": "attachments/",
"_ts": 1562284141
}
型号:
namespace PelicanboatRamp.Models
{
public class Weather
{
[JsonProperty(PropertyName = "id")]
public string Id { get; set; }
[JsonProperty(PropertyName = "DateTime")]
public DateTime Datetime { get; set; }
public static DateTime Today { get; }
[JsonProperty(PropertyName = "LocationId")]
public string LocationId { get; set; }
[JsonProperty(PropertyName = "Entries")]
public Entries entries { get; set; }
}
public class Entries
{
[JsonProperty(PropertyName = "precisCode")]
public string Forecast { get; set; }
[JsonProperty(PropertyName = "min")]
public int MinTemp { get; set; }
[JsonProperty(PropertyName = "max")]
public int MaxTemp { get; set; }
}
}
Controller :
public class WeatherController : Controller
{
// GET: Weather
[ActionName("Index")]
public async Task<ActionResult> IndexAsync()
{
DateTime thisDay = DateTime.Today;
var items = await DocumentDBRepository<Weather>.GetWeatherAsync(d => d.Id != null);
items.Select(t => new Entries
{ Datetime = t.Datetime,
Forecast = t.entries.Forecast,
MinTemp = t.entries.MinTemp,
MaxTemp = t.entries.MaxTemp
}).ToList();
return View(items);
}
}
文档数据库存储库:
public static async Task<IEnumerable<T>> GetWeatherAsync(Expression<Func<T, bool>> predicate)
{
IDocumentQuery<T> query = client.CreateDocumentQuery<T>(
UriFactory.CreateDocumentCollectionUri(DatabaseId, CollectionId),
new FeedOptions { MaxItemCount = 10, EnableCrossPartitionQuery = true })
.Where(predicate)
.AsDocumentQuery();
List<T> results = new List<T>();
while (query.HasMoreResults)
{
results.AddRange(await query.ExecuteNextAsync<T>());
}
return results;
}
public static async Task<T> GetWeatherAsync(string LocationId, string id)
{
try
{
//RequestOptions feedOptions = new RequestOptions { PartitionKey = new PartitionKey(Year) };
Document document = await client.ReadDocumentAsync(UriFactory.CreateDocumentUri(DatabaseId, CollectionId, id), new RequestOptions { PartitionKey = new PartitionKey(LocationId) });
return (T)(dynamic)document;
}
catch (DocumentClientException e)
{
if (e.StatusCode == System.Net.HttpStatusCode.NotFound)
{
return null;
}
else
{
throw;
}
}
}
}
索引:
@model IEnumerable<PelicanboatRamp.Models.Weather>
@{
ViewBag.Title = "Index";
Layout = "~/Views/Shared/_Layout.cshtml";
}
<h2>Todays Weather</h2>
@foreach (var item in Model)
{
DateTime mydatetime = DateTime.Now;
<h3>
DateTime: @mydatetime
</h3>
<h3>
Forecast:@Html.DisplayFor(modelItem => item.entries.Forecast)
</h3>
<h3>
MinTemp: @Html.DisplayFor(modelItem => item.entries.MinTemp)
</h3>
<h3>
MaxTemp @Html.DisplayFor(modelItem => item.entries.MaxTemp)
</h3>
}
我想显示: (当前日期和时间 预报:“阵雨”， 最低温度:10， 最高温度:19
不显示天气预报、最低温度和最高温度
最佳答案
第一个问题
模型类不正确地反射(reflect) JSON 结构。这里:
"Entries": {
"0": {
"dateTime": "2019-07-04T00:00:00",
"precisCode": "showers-rain",
"min": 10,
"max": 19
}
}
Entries是一个包含数字键 0 的对象，我猜可能包含 1 , 2等。每个数字键下都有一个条目对象。
为了在 C# 中表示这样的结构，我们应该使用字典，例如 Dictionary<string, Entry> (让我们将 Entries 重命名为 Entry ，因为它应该代表单个条目对象)。以下是正确的模型:
public class Weather
{
// ... other properties
// this property was declared incorrectly
[JsonProperty(PropertyName = "Entries")]
public Dictionary<string, Entry> Entries { get; set; }
}
// renamed from Entries
public class Entry
{
// ... properties
}
第二个问题
在 View 中，模型声明为IEnumerable<...>虽然您似乎想要访问 Weather 的单个实例。列出所有 Weather 中的所有条目查询返回的对象，您应该循环 Model像这样:
@{
DateTime mydatetime = DateTime.Now;
var allEntries = Model.SelectMany(m => m.Entries.Values);
}
@foreach (var entry in allEntries)
{
<h3>
DateTime: @mydatetime
</h3>
<h3>
Forecast:@Html.DisplayFor(modelItem => entry.Forecast)
</h3>
<h3>
MinTemp: @Html.DisplayFor(modelItem => entry.MinTemp)
</h3>
<h3>
MaxTemp @Html.DisplayFor(modelItem => entry.MaxTemp)
</h3>
}
顺便说一句， Controller 中的这段代码:
items.Select(t => new Entries {
Datetime = t.Datetime,
Forecast = t.entries.Forecast,
MinTemp = t.entries.MinTemp,
MaxTemp = t.entries.MaxTemp
}).ToList();
完全是多余的，没有任何效果。
如果您只想显示单个天气对象
然后在 View 中，将模型更改为 Weather 类型，并相应地更改循环，如下所示:
@model PelicanboatRamp.Models.Weather
@{
ViewBag.Title = "Index";
Layout = "~/Views/Shared/_Layout.cshtml";
}
@{
DateTime mydatetime = DateTime.Now;
}
@foreach (var entry in Model.Entries.Values)
{
<h3>
DateTime: @mydatetime
</h3>
<h3>
Forecast:@Html.DisplayFor(modelItem => entry.Forecast)
</h3>
<h3>
MinTemp: @Html.DisplayFor(modelItem => entry.MinTemp)
</h3>
<h3>
MaxTemp @Html.DisplayFor(modelItem => entry.MaxTemp)
</h3>
}
在 Controller 中，选择一个 Weather传递给 View 的对象:
[ActionName("Index")]
public async Task<ActionResult> IndexAsync()
{
DateTime thisDay = DateTime.Today;
var items = await DocumentDBRepository<Weather>.GetWeatherAsync(d => d.Id != null);
// select a single Weather object according to your business logic
// for example like this:
var todaysWeather = items.Single(weather => weather.DateTime.Date == thisDay);
// pass the single Weather to the view
return View(todaysWeather);
}
关于c# - 使用 C# ASP.NET MVC 显示来自单个数组 JSON(azure Cosmos db) 的数据，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/56928088/