using System;

​

public class Program

{

    public static void Main()

    {

        var test = GetContainsColorsParams(null);

        Console.WriteLine(test);

    }

​

    public static string GetContainsColorsParams(string[] list)

    {

        var result = string.Empty;

        if (list == null || list.Length == 0)

        {

            result = string.Format("'00018', '00034'");

        }

        else

        {

            foreach (var item in list)

            {

                result += "'" + item + "',";

            }

        }

​

        result = result.Remove(result.Length - 1);

        return result;

    }

}