How to change the order by a result using linq based on the generic list values.

My opinion is that this is a case where using Linq ... while perhaps possible ... is probably "over-kill" because: what you are really doing is quite arbitrary. If I understand your goal, it is to move entries in a query result that match entries in another list to the front of the query result.

For the case that your query result doesn't contain duplicate values, you can use something like this:

private List<int> queryList = new List<int> {11, 42, 65, 33, 3, 5, 65, 5, 8};
        
private List<int>sortByList = new List<int> {65, 123, 42, 11};

int sortByInt;
int matchAt;

// somewhere in a method ...

// traverse the sortByList from back to front
// based on the assumption the desired result
// is a sort based on magnitude
for (int i = sortByList.Count - 1; i >= 0; i--)
{
    sortByInt = sortByList[i];

    if (queryList.Contains(sortByInt))
    {
        matchAt = queryList.IndexOf(sortByInt);
        queryList.RemoveAt(matchAt);
        queryList.Insert(0, sortByInt);
    }
}

That would handle the case of having entries in the sort-by list that do not occur in the query list.

By comparing the Integer list with Linq result set (with key element) added the data to the new list and used this new list for further process. This resolved my problem.