JsonSerializer.Deserialize always returns Null

Question

Trying to deserialize the following json string:

string json = "{\"d\":{\"__metadata\":{\"id\":\"http://my.dev.int:8000/sap/opu/odata/sap/ZFIORI_SERIAL_NUMBERS_SRV/MATERIALSet('250')\",\"uri\":\"http://my.dev.int:8000/sap/opu/odata/sap/ZFIORI_SERIAL_NUMBERS_SRV/MATERIALSet('250')\",\"type\":\"ZFIORI_SERIAL_NUMBERS_SRV.MATERIAL\"},\"MATNR\":\"250\",\"MAKTX\":\"X:K10/MF250\"}}";

into Class Object

namespace Scanner.Model
{
    public class Material
    {
        public string MATNR { get; set; }
        public string MAKTX { get; set; }
    }
}

I have tried using many ways including :

Material material = JsonSerializer.Deserialize<Material>(json, new JsonSerializerOptions
{
    PropertyNameCaseInsensitive = true,
    IgnoreNullValues = true,
    PropertyNamingPolicy = JsonNamingPolicy.CamelCase,
});


Console.WriteLine(material.MATNR); //expected output: 250
Console.WriteLine(material.MAKTX); //expected  output: X:K10/MF250

But material.MATNR and material.MAKTX are always null .

You can´t decode it like that. Your json has a completly different structure. Try json2csharp to create a proper model. — burnsi, Feb 20 '23 at 18:47
Thank you for the tool ... looks cool il sure use it going forward . — Mlamuli Zondo, Feb 20 '23 at 19:06

Ryan Wilson · Accepted Answer · 2023-02-20T19:00:44.110

I think you need to familiarize yourself more with the Json structure, Material is not the type of object being returned in your Json string, it is a nested class of the main object, I have put together a dot net fiddle and tested that this will work for you, as you can see, the main object is what I called MyJson which holds one property of class type MetaData and a property name of d, this class then contains 3 properties: of type MetaBase which contains 3 properties of string types and 2 other string properties, I then deserialize the json string to the main object type of MyJson and then write the nested property MATNR to the console window, this prints 250, I'm also using, JsonPropertyNameAttribute to set certain class properties to the matching values in the json string, you can read more about that here:system.text.json.serialization.jsonpropertynameattribute fiddle here: dotnet-fiddle:

using System;
using System.Text.Json;
using System.Text.Json.Serialization;
public class Program
{
    public static void Main()
    {
        string json = "{\"d\":{\"__metadata\":{\"id\":\"http://my.dev.int:8000/sap/opu/odata/sap/ZFIORI_SERIAL_NUMBERS_SRV/MATERIALSet('250')\",\"uri\":\"http://my.dev.int:8000/sap/opu/odata/sap/ZFIORI_SERIAL_NUMBERS_SRV/MATERIALSet('250')\",\"type\":\"ZFIORI_SERIAL_NUMBERS_SRV.MATERIAL\"},\"MATNR\":\"250\",\"MAKTX\":\"X:K10/MF250\"}}";
        var myjson = System.Text.Json.JsonSerializer.Deserialize<MyJson>(json);
        Console.WriteLine(myjson.D.MATNR);
    }
}

public class MyJson
{
    [JsonPropertyName("d")]
    public MetaData D {get; set;}
}

public class MetaData
{
   [JsonPropertyName("__metadata")]
   public MetaBase MetaB {get; set;}
   public string MATNR { get; set; }
   public string MAKTX { get; set; }    
    
}

public class MetaBase
{
   [JsonPropertyName("id")]
   public string ID {get; set;}
   [JsonPropertyName("uri")]
   public string Uri {get; set;}
   [JsonPropertyName("type")]
   public string Type {get; set;}
    
}

Thank a million , works like a charm . Thank you . I am new to C# and thought the deserializer takes care of the sub objects .Thank you . — Mlamuli Zondo, Feb 20 '23 at 18:49

Serge · Answer 2 · 2023-02-20T20:17:57.697

0

Since you need only Material

Material material = System.Text.Json.Nodes.JsonNode.Parse(json)["d"].Deserialize<Material>();

edited Feb 20 '23 at 20:17

answered Feb 20 '23 at 20:11

Serge

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JsonSerializer.Deserialize always returns Null

2 Answers2