对包含对象列表的JSON对象进行脱盐处理为嵌套对象返回Null

Question

This is my first attempt of working with JSON deserialization. I have read many of the posts in Stackoverflow, non of the suggested solutions could match my issue, so my apology in advance. I have created the following objects:

public class Item
{
    public int ID { get; set; }
    public int LSum { get; set; }
    public int YSum { get; set; }
    public int TSum { get; set; }
    public int NSum { get; set; }
    public int MemberId { get; set; }
}

public class Something
{
    public int Id { get; set; }
    public string Phone { get; set; }
    public bool ExistingMember { get; set; }
    public IList<Item> Item { get; set; }
}

And when deserialize the JSON it looks like following: The follwoing JSON what I expect it to be:

    {
   "Id":62,
   "Phone":"07",
   "ExistingMember":true,
   "Item":[
      {
         "ID":42,
         "LSum":0,
         "YSum":0,
         "TSum":0,
         "NSum":0,
         "MemberId":12
      }
   ]
}

However the following method it

   some= JsonConvert.DeserializeObject<something>(someResponse);

It prints the json like the following: The following JSON is what is "someResponse" return,

{
   "Id":62,
   "Phone":"07",
   "ExistingMember":true,
   "Item":null
}

What am I missing that the item list is return null?

Answer 1

If you want to deserialize json string which in your case is someResponse variable, then you are doing it right.

To check your code I created a JSON file with a file.json name and put the following on it:

{
  "Id": 62,
  "Phone": "07",
  "ExistingMember": true,
  "Item": [
    {
      "ID": 42,
      "LSum": 0,
      "YSum": 0,
      "TSum": 0,
      "NSum": 0,
      "MemberId": 12
    }
  ]
}

Then below lines of code take the content of JSON file (which in your case is the content of someResponse ) and deserialize it into c# object of Something type:

string jsonFilePath = @"C:\test\file.json";

var some = JsonConvert.DeserializeObject<Something>(File.ReadAllText(jsonFilePath));

Then print the ID property of each element of Item list:

foreach(var item in some.Item)
{
    if (item != null)
    {
        Console.WriteLine($"item ID = {item.ID}");
    }               
}

The output:

item ID = 42

So, it is quite possible that someResponse just does not have an Item and looks like this:

{
  "Id": 62,
  "Phone": "07",
  "ExistingMember": true
}

UPDATE:

Also I tried like this:

var someResponse = @"{
  'Id': 62,
  'Phone': '07',
  'ExistingMember': true,
  'Item':[
    {
      'ID': 42,
      'LSum': 0,
      'YSum': 0,
      'TSum': 0,
      'NSum': 0,
      'MemberId': 12
    }
  ]
}
";

var some = JsonConvert.DeserializeObject<Something>(someResponse);

And some has a Item list with 1 element