Jsonconvert.deserialize to class returns null

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I’m attempting to deserialize the following Json string to c# .net class list collection, but the Jsonconvert.deserialize returns null. Can someone please explain to me what I’m doing wrong.

string strjson = "{ 'TestInfo':[{'testId':1,'testShortDescription':'TankTest','testLongDescription':'Tank Test ','testTypeId':2,'testLimitsId':null},{'testId':2,'testShortDescription':'FuelPump1','testLongDescription':'Fuel Pump 1','testTypeId':4,'testLimitsId':null},{'testId':3,'testShortDescription':'FuelPump2','testLongDescription':'Fuel Pump 2','testTypeId':4,'testLimitsId':null},{'testId':4,'testShortDescription':'TankAudit','testLongDescription':'Tank Chamber Audit','testTypeId':6,'testLimitsId':null}]}";
                      TestInfoCollectionCS testinfocollection = JsonConvert.DeserializeObject<TestInfoCollectionCS>(strjson);

Here is the collection class:

using System;
using System.Collections.Generic;
using System.Text;
using TestITMobileApp.Model;

namespace TestITMobileApp.App_Data
{
    public class TestInfoCollectionCS
    {
        private List<TestInfoCS> testinfocollection;

        public List<TestInfoCS> TestInfoCollection { get => testinfocollection; set => testinfocollection = value; }
    }
}

Here is the call:

using System;
using System.Collections.Generic;
using System.ComponentModel;

namespace TestITMobileApp.Model
{
    public class TestInfoCS 
    {
        #region "Private variables""
        private int testId;
        private string testShortDescription;
        private string testLongDescription;
        private int? testTypeId;
        private int? testLimitsId;
        #endregion
        #region "Properties"
        #region "TestID"
        public int TestID { get => testId; set => testId = value; }
        #endregion
        #region "TestShortDescription"
        public string TestShortDescription { get => testShortDescription; set => testShortDescription = value; }
        #endregion
        #region "TestLongDescription"
        public string TestLongDescription { get => testLongDescription; set => testLongDescription = value; }
        #endregion
        #region "TestTypeId"
        public int? TestTypeId  { get => testTypeId; set => testTypeId = value; }
        #endregion
        #region "TestLimitsId"
        public int? TestLimitsId { get => testLimitsId; set => testLimitsId = value; }
        #endregion
        #endregion
    }
}

What I have tried:

Tried running the above code, but json convert deserialization returns null.

Posted 12-Feb-19 8:18am

Paul Dietz

Updated 7-Oct-19 4:37am

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3 solutions

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Gerry Schmitz · Answer 1 · 2019-02-12T08:59:00

Solution 1

The "case" doesn't match.

The JSON element names are lower case; the class properties are upper case (the fields are lower case and not accessible).

Posted 12-Feb-19 8:59am

Gerry Schmitz

Updated 12-Feb-19 9:01am

v2

Comments

vinodambadi 23-Aug-23 7:22am

Thanks this helped

ksk · Answer 2 · 2019-10-07T04:37:00

TestInfo node in the JSON does not match to the property TestInfoCollection.
JsonConvert.DeserializeObject can leave reference type member properties null during deserialization without [JsonProperty] attribute on the property.

Try this:

1. Synchronize the property name in the class and in the JSON file.
2. Add [JsonProperty] attribute to the property in the C# class.

Or add attribute [JsonProperty("TestInfo")] to the TestInfoCollection property.

// Both of these approaches helped me in the same situation.

Randy Kroeger · Answer 3 · 2023-08-28T08:30:00

Solution 3

What I have done in the past, where the serializer is returning null on Deserialize, is to test Serializing my object to see what the serializer is expecting. Once I see that result, I can fix my objects so they now Deserialize correctly.

Posted 28-Aug-23 8:30am

Randy Kroeger