Filtering out the set difference of two List<JObject> in C# using LINQ

Question

I have 2 List<JObject> to be compared for their set differences,

The format of the two List<JObject> to be compared are as follows:

This is the JSON structure for my base List<JObject> :

[
    {
        "name": "competency",
        "subLists": [
            {
                "canonicalForm": "c1",
                "list": [
                    "c one",
                    "c 1",
                    "cone",
                    "Cone"
                ]
            }
        ],
        "roles": []
    },
    {
        "name": "demoList",
        "subLists": [],
        "roles": []
    }
]

---

This is the JSON structure of the List<JObject> that I want to find the set difference against:

[
    {
        "name": "competency",
        "subLists": [
            {
                "canonicalForm": "c1",
                "list": [
                    "c one",
                    "c 1",
                    "cone",
                    "Cone",
                    "C ONE"
                ]
            },
            {
                "canonicalForm": "c2",
                "list": [
                    "c two",
                    "c 2"
                ]
            }
        ],
        "roles": []
    },
    {
        "name": "leavetype",
        "subLists": [
            {
                "canonicalForm": "annual",
                "list": [
                    "Easter"
                ]
            }
        ],
        "roles": []
    },
    {
        "name": "demoList",
        "subLists": [],
        "roles": []
    }
]

---

With the output set difference JSON being:

[
    {
        "name": "competency",
        "subLists": [
            {
                "canonicalForm": "c1",
                "list": [
                    "c one",
                    "c 1",
                    "cone",
                    "Cone",
                    "C ONE"
                ]
            },
            {
                "canonicalForm": "c2",
                "list": [
                    "c two",
                    "c 2"
                ]
            }
        ],
        "roles": []
    },
    {
        "name": "leavetype",
        "subLists": [
            {
                "canonicalForm": "annual",
                "list": [
                    "Easter"
                ]
            }
        ],
        "roles": []
    }
]

---

I have tried using the following code using two for-loops:

List<JObject> baseList = JsonConvert.DeserializeObject<List<JObject>>(baseListString);
List<JObject> comparedList = JsonConvert.DeserializeObject<List<JObject>>(comparedListString);

List<JObject> finalResultList = new List<JObject>();


for (int i = 0; i < baseList.Count; i++)
{
     for (int j = 0; i < comparedList.Count; j++)
     {
        if(baseList[i]["subLists"] != comparedList[j]["subLists"])
                        finalResultList.Add(comparedList[j]);
     }
}

But this is not cutting it, I want to compare the entire JObject based on the key values of name, canonicalForm, list keys and filter out the set difference using LINQ. But I am unable to do so.

I have tried using .Except() extension method but that is not working as well.

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Edit:

I want to check if there is any change in the 3 keys which are: name, canonicalForm and list, if there are any change in the compareObject compared to the BaseObject I want to return the JObject which has the change. The output is displayed above.

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Any help will be appreciated.

Answer 1

I finally solved my problem by implementing the IEqualityComparer for JObject.

---

Here is my JObjectEqualityComparer class:

public class JObjectEqualityComparer : IEqualityComparer<JObject>
    {
        public bool Equals(JObject x, JObject y)
        {
            if (x == null && y == null)
                return true;
            if ((x != null && y == null) || (x == null && y != null))
                return false;

            return JObject.DeepEquals(x, y);
        }

        public int GetHashCode(JObject obj)
        {
            JTokenEqualityComparer comparer = new JTokenEqualityComparer();
            int hashCode = comparer.GetHashCode(obj);
            return hashCode;
        }
    }

---

Finally I have used this overload of .Except() extension method to find the Set Difference.

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Here is the code:

List<JObject> baseList = JsonConvert.DeserializeObject<List<JObject>>(baseListString);
List<JObject> comparedList = JsonConvert.DeserializeObject<List<JObject>>(comparedListString);

List<JObject> finalResultList = new List<JObject>();

finalResultList = comparedList.Except(baseList, new JObjectEqualityComparer()).ToList();

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Thanks to Ed Plunkett, dbc and Coding Yoshi for pointing me out in the correct direction.