using System;

using System.Collections.Generic;

public class Program

{

    public static void Main()

    {

        string searchDuration = "200";

​

        var response = new Dictionary<string, string>()

        {

            {"searchDuration","10"},

            {"minRssi", "-70"},

            {"optionalFilter","NO_FILTERS_ACTIVE_SCANNING"},

            {"txPowerLevel","200"},

            {"peripheralId","123wrong"}

        };

​

        var wasItThere = response.TryGetValue(nameof(searchDuration), out var value);

        Console.WriteLine(wasItThere);

        Console.WriteLine(wasItThere && (value == searchDuration));

    }

}