在 Dotnet Core MVC 中填充下拉列表 - 从动态 JSON 产品 URL 解析

Question

示例 JSON 文件：

{ "products" : [{ "Name": "Cheese", "Price" : 2.50, "Location": "Refrigerated foods"},{ "Name": "Crisps", "Price" : 3, "Location": "the Snack isle"},  { "Name": "Pizza", "Price" : 4, "Location": "Refrigerated foods"},  { "Name": "Chocolate", "Price" : 1.50, "Location": "the Snack isle"},  { "Name": "Self-raising flour", "Price" : 1.50, "Location": "Home baking"},  { "Name": "Ground almonds", "Price" : 3, "Location": "Home baking"}]}

Controller.cs 代码

 public IActionResult Index()
    {
        var webClient = new WebClient();
        //var jsonUrlProducts = webClient.DownloadString(@"https://raw.githubusercontent.com/mdn/fetch-examples/master/fetch-json/products.json");
        var jsonUrlProducts = webClient.DownloadString(@"C:\Users\NatarajanS\source\repos\KC_EC_WebSite_1\KC_EC_WebSite_1\wwwroot\lib\JSON\Json_F3.json");

        var dictProducts = JsonConvert.DeserializeObject<Dictionary<string, object>>(jsonUrlProducts);

        ViewData["selectedProductTextDict"] = dictProducts;             
     
        return View();
    }

Index.cshtml 代码：

 @Html.DropDownList("ddlProductByText",
       new SelectList((System.Collections.IEnumerable)ViewData["selectedProductTextDict"], "Value", "Key"))

{ "products" : [{ "Name": "Cheese", "Price" : 2.50, "Location": "Refrigerated foods"}] }

我需要使用对象键名称填充我的下拉列表。来自上述 JSON 文件的示例 .. 名称、价格、位置

但上面的代码只填充了我的根对象名称products。

Answer 1

Dropdownlist values 正如Atabai所说，你需要创建一个模型来映射json。对于你的json，模型设计应该是：

public class Test
{
    public List<Product> products { get; set; }
}

public class Product
{
    public string Name { get; set; }
    public float Price { get; set; }
    public string Location { get; set; }
}

控制器：

[HttpGet]
public ActionResult Index()
{
    //....
    var dictProducts = JsonConvert.DeserializeObject<Test>(jsonUrlProducts);

    ViewData["selectedProductTextDict"] = dictProducts.products;
    return View();
}

查看（例如填充姓名列表）：

@Html.DropDownList("ddlProductByText",
      new SelectList((System.Collections.IEnumerable)ViewData["selectedProductTextDict"], "Name", "Name"))

结果：

更新：

如果您只想显示名称、价格、位置，请检查以下代码：

[HttpGet]
public ActionResult Index()
{
       //...
        var dictProducts = JsonConvert.DeserializeObject<Dictionary<string,object>>(jsonUrlProducts);
        var data =(JArray)dictProducts["products"];
        Dictionary<string, string> dic = new Dictionary<string, string>();
        foreach (JObject obj in data.Children())
        {
            foreach (JProperty prop in obj.Children())
            {
                string key = prop.Name.ToString();
                string value = prop.Value.ToString();
                dic.Add(key, value);
            }
            break;
        }          
        ViewData["selectedProductTextDict"] = dic;
        return View();
}

查看：

@Html.DropDownList("ddlProductByText",
      new SelectList((System.Collections.IEnumerable)ViewData["selectedProductTextDict"], "Value", "Key"))

结果：

Answer 2

我认为你必须创建类对象并使用它，就像下面的代码：

    public class Product    {
        public string Name { get; set; } 
        public double Price { get; set; } 
        public string Location { get; set; } 
    }

它可以帮助您访问所有道具。