c# - Json.NET Dictionary<string,T> with StringComparer serialization

Question

I have a dictionary Dictionary<string, Dictionary<string, object>>. Both the outer dictionary and the inner one have an equality comparer set(in my case it is StringComparer.OrdinalIgnoreCase). After the dictionary is serialized and deserialized the comparer for both dictionaries is not set to StringComparer.OrdinalIgnoreCase.

If you have control over the creation of the dictionaries in your code, you can create a class inherited from the dictionary and set comparer in the default constructor of the class. But what if you do not have control over dictionary creation and you get the dictionary from the other code?

Is there any way to serialize/deserialize it correctly with the comparer?

Answer 1

One simple idea would be to create a subclass of Dictionary<string, string> that sets the comparer to StringComparer.OrdinalIgnoreCase by default, then deserialize into that instead of the normal dictionary. For example:

class CaseInsensitiveDictionary<V> : Dictionary<string, V>
{
    public CaseInsensitiveDictionary() : base(StringComparer.OrdinalIgnoreCase)
    {
    }
}

class Program
{
    static void Main(string[] args)
    {
        string json = @"
        {
            ""Foo"" : 
            {
                ""fiZZ"" : 1,
                ""BUzz"" : ""yo""
            },
            ""BAR"" :
            {
                ""dIt"" : 3.14,
                ""DaH"" : true
            }
        }";

        var dict = JsonConvert.DeserializeObject<CaseInsensitiveDictionary<CaseInsensitiveDictionary<object>>>(json);

        Console.WriteLine(dict["foo"]["fizz"]);
        Console.WriteLine(dict["foo"]["buzz"]);
        Console.WriteLine(dict["bar"]["dit"]);
        Console.WriteLine(dict["bar"]["dah"]);
    }
}

Output:

1
yo
3.14
True