using System;

using System.Collections.Generic;

​

public class Program{

    public static void Main(string[] args){

        Test objTest = new Test();

        IDictionary<string, string[]> lDict2 = new Dictionary<string, string[]>();

        lDict2 = objTest.TestMethod();

        string[] fArray = lDict2["First List"];

        string[] sArray = lDict2["Second List"];

        Console.WriteLine("items in the first array: ");

        foreach(var item in fArray){

            Console.WriteLine(item);

        }

        Console.WriteLine(lDict2["First List"][0]);

        Console.WriteLine("items in the second array: ");

        foreach(var item in sArray){

            Console.WriteLine(item);

        }

    }

}

​

public class Test{

    public IDictionary<string, string[]> TestMethod(){

        const string first = "First List";

        const string second = "Second List";

        bool indicator = true;

        List<string> fList = new List<string>(){ "one", "two", };

        List<string> sList = new List<string>(){ "three", "four", };

        Dictionary<string, List<string>> lDict = new Dictionary<string, List<string>>();

        // Putting the lists into dictionary

        lDict.Add(first, fList);

        lDict.Add(second, sList);

        if(indicator){

            foreach(KeyValuePair<string, List<string>> item in lDict){

                item.Value.Clear();

            }

            foreach(var key in lDict.Keys){

                lDict[key].Add("hi");

            }

        }

        IDictionary<string, string[]> lDict2 = new Dictionary<string, string[]>();

        foreach(var item in lDict){

            lDict2[item.Key] = item.Value.ToArray();

        }

        return lDict2;

    }

}