将 JSON 字符串解析为列表

Question

It is needed to parse JSONString into List. (List of instances) I'm trying to use JSON.NET by Newtonsoft.

I have classes:

    public class Item
    {
        public int ID { get; set; }
        public string Name { get; set; }
        public string Url { get; set; }
        public string Manufactorers { get; set; }

    }

The JSON string looks something like this:

[
{     
 "Column0":23.0,
 "Column1":"Евроен",
 "Column2":"https://www.123.com",
 "Column3":"Фак"
},
{
 "Column0":24.0,
 "Column1":"Еил",
 "Column2":"https://www.123.com",
 "Column3":"Старт"
}
]

I've been trying to do something like this:

string JSONString = string.Empty;
JSONString = JsonConvert.SerializeObject(result);
List<Item> items = JsonConvert.DeserializeObject<List<Item>>(JSONString);

But it returns 0 and null. I have no idea, how to fix it.

Also here I truy to parse Excel file. This code works, but after deserialization, I have just 0 and null.

var filePath = @"..\..\..\..\doc.xlsx";

using (var steam = File.Open(filePath, FileMode.Open, FileAccess.Read))
{
   using (var reader = ExcelReaderFactory.CreateReader(steam))
   {
       var result = reader.AsDataSet().Tables["Лист1"];

       string JSONString = string.Empty;
       JSONString = JsonConvert.SerializeObject(result);

       List<Item> items = JsonConvert.DeserializeObject<List<Item>>(JSONString);

    }
}

Answer 1

The naming of JSON and your class does not match. This can be fixed using JsonProperty attributes:

[JsonProperty("Column0")]
public decimal ID { get; set; }

Second, JSON deserizlizer can not deserialize string "23.0" to int when there is decimal point. You can retype ID to decimal or double to make it work.

Little test here:

public class TestClass
{
    [JsonProperty("Column0")]
    public decimal ID { get; set; }
}

Then the deserialization works without errors:

var testClassJson = "{\"Column0\": 12.0}";
var i = JsonConvert.DeserializeObject<TestClass>(testClassJson);