How to reflection check nullable object is IDictionary

Question

How to reflection check nullable object is IDictionary

eg:

if object is not null it can use is keyword to check.

void Main()
{
    Dictionary<string, object> v = new Dictionary<string,object>();
    Console.WriteLine(CheckValueIsIDictionary(v)); //true
}

bool CheckValueIsIDictionary(object value){
    return value is IDictionary;
}

but if parameter value is null then will get false

void Main()
{
    Dictionary<string, object> v = null;
    Console.WriteLine(CheckValueIsIDictionary(v)); //false
}

bool CheckValueIsIDictionary(object value){
    return value is IDictionary;
}

I expect get true result, thanks!

---

update:

I want to check value declare type is a IDictionary

before example you can know this null value is from Dictionary<string,object> and this type is a IDictionary and I want to get the relationship result.

and why I'd like to do it:

I want to check values is IDictionary or not to do different logic, object value can be Array or Dictionary<int,int> or List

Answer 1

You can only do this with type inference and generics:

public static bool CheckValueIsIDictionary<T>(T value)
{
    Type typeT = typeof(T);
    return value is IDictionary || typeof(IDictionary).IsAssignableFrom(typeof(T));
}

Obviously if you have something like this, you'll get false :

Dictionary<string, string> myDictionary = null;
object o = myDictionary;
Console.WriteLine(CheckValueIsIDictionary(o));

But it will work where there is a value, or where the type is known at compile time.