looping through JSON object at adding each record to list c#

Question

I'm a bit new to c#, and I am trying to add all the records I return back from my web service and add them to their designated list. My JSON looks something like this:

{
  
 "errMsg":"",
   "date":"2020-10-21 10:20:28",
   "Category":
   [{"iCatID":"1","sDescription":"All},{"iCatID":"2","sDescription":"All Vegetables"},....],
 "Product":
   [{"iProductID":"10","sDescription":"Apples},   {"iProductID":"11","sDescription":"All Vegetables"},....]
}

Both Products and Categories are returning several 100 or 1000 products. SO far I have this to try and iterate through them and add them to their own list to then add both lists to Two local tables I have in my app called Product and Category.

I am clearly doing something wrong because my current code is not working. private List _product = new List(); private List _category = new List();

public async void CreateLocalTables()    
{

try
          {
            _client.GetAsync("https://app.spcty.com/app/dbExport.php");
                var content = await response.Content.ReadAsStringAsync();
                dynamic data = JsonConvert.DeserializeObject(content);

             foreach (var obj in data.Product)
              {
                  Console.WriteLine(obj);
                  //does not work
                  _product.Add(obj)
              }
}

My error is as follows Microsoft.CSharp.RuntimeBinder.RuntimeBinderException: The best overloaded method match for 'System.Collections.Generic.List<Project.Models.Category>.Add(Project.Models.Category)' has some invalid arguments

I checked out my Category Class and I think I have everything I need.

public class Category
    {

        [PrimaryKey]
        public int iCatID { get; set; }
        public string sDescription { get; set; }
}

I don't get what it says invalid arguments. I get this for both category and product. Any recommendations? EDIT: I have also tried it this using the RootObject, I just didn't know how to access the product and category lists from there:

public class RootObject
{
    public  List<Category> CategoyItems { get; set; }

    public List<Product> ProductItems { get; set; }
    public string errMsg { get; set; }
    public string date { get; set; }            
}

I added two more things to both the JSON and RootObject.

Hi, could you show the example content data of response.Content.ReadAsStringAsync()? I will check the structure of data . — Junior Jiang
– Junior Jiang, Commented Oct 21, 2020 at 6:29
@JuniorJiang-MSFT I added more of my JSON and I also added things to it, hopefully that gives you a better description. — Cookies
– Cookies, Commented Oct 21, 2020 at 17:30
Okey, thanks for updating. If you have solved this, remember to mark the answer when you have time. It will be helpful for other people to know the solution. — Junior Jiang
– Junior Jiang, Commented Oct 22, 2020 at 3:06

Jason · Accepted Answer · 2020-10-21 02:49:34Z

1

you need to deserialize your data into a concrete type

var data = JsonConvert.DeserializeObject<RootObject>(content);

foreach(var obj in data.ProductItems)
{
  _product.Add(obj);
}

edited Oct 21, 2020 at 2:49

answered Oct 21, 2020 at 2:30

Jason

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5 Comments

Cookies Over a year ago

but my JSON data includes Category as well. I am pulling multiple arrays at once. One is Product and the other one is Category, that is why I had tried using dynamic.

Cookies Over a year ago

okay so oddly enough now I am getting this error System.NullReferenceException: Object reference not set to an instance of an object in the line ''foreach(var obj in data.ProductItems)''. Do you know why that may be?

Jason Over a year ago

Because ProductItems is null. There is nothing with that name in your JSON so unless you have a mapping attribute it won’t deserialize correctly

Cookies Over a year ago

ah I see. Okay I fixed that. I think I am on the right track now because I am getting this error now Cannot deserialize the current JSON object (e.g. {"name":"value"}) into type 'System.Collections.Generic.List`1[SPRecipeApp2020.Models.Category_Type]' because the type requires a JSON array (e.g. [1,2,3]) to deserialize correctly. I've dealt with that error before so I will dive into it

Cookies Over a year ago

thanks again for you help. I had some issues in my JSON. But this worked

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