c# - ASP.net 如何解析 JSON

Question

我正在尝试让网页返回 iTunes 搜索结果。在查看这里的一些结果以解决类似问题时，我将这段代码放在一起，但是我得到了错误：System.Collections.Generic.KeyNotFoundException：'给定的键不存在于第 41 行的字典中：

string trackName = obj2["trackname"].ToString();

任何帮助是极大的赞赏。

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Script.Serialization;
using System.Web.UI;
using System.Web.UI.WebControls;

namespace Project4
{
public partial class project4a : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {

    }

    protected void Button1_Click(object sender, EventArgs e)
    {
        string choice="";
        if (TextBox1.Equals("Music"))
        {
            choice = "musicTrack";
        }else if (TextBox1.Equals("Movie"))
        {
            choice = "movie";
        }else if (TextBox1.Equals("Software"))
        {
            choice = "software";
        }
        string url = "https://itunes.apple.com/search?term=" + TextBox1.Text.ToString() + "&entity="+choice ; //+DropDownList1.SelectedValue.ToString()
        using (var webClient = new System.Net.WebClient())
        {
            var json = webClient.DownloadString(url);
            //parse
            JavaScriptSerializer jsSerializer = new JavaScriptSerializer();
            var result = jsSerializer.DeserializeObject(json);
            Dictionary<string, object> obj2 = new Dictionary<string, object>();
            obj2 = (Dictionary<string, object>)(result);

            string trackName = obj2["trackname"].ToString();




            Label3.Text = trackName;

        }
    }
}
}

标签： c#asp.netjsonparsing

Answer 1

我认为从 API 调用返回的 json 如下所示：

{ 结果计数：数字，结果：数组 }

因此，字典中有 2 个值，一个用于键“resultCount”，一个用于键“results”。

你想要做的是反序列化结果数组，然后查询：

JavaScriptSerializer jsSerializer = new JavaScriptSerializer();
var result = jsSerializer.DeserializeObject(File.ReadAllText(@"C:\Users\Simon\Downloads\1.txt"));
Dictionary<string, object> obj2 = new Dictionary<string, object>();
obj2 = (Dictionary<string, object>)(result);

object[] resultsList = (object[])obj2["results"];

foreach (var r in resultsList)
{
    Dictionary<string, object> obj3 = (Dictionary<string, object>) r;
    string trackName = obj3["trackName"].ToString();
}