using System;

using System.Web;

using System.ComponentModel;

using System.Globalization;

public class Program

{

    public interface IReports

    {

        string TaskList(int tenantID, int employeeID,

            DateTimeOffset DateStart,

          DateTimeOffset DateEnd,

          string CustomerNumber,

          int? ProductID,

          int? ProductGroupID,

          string ObjectCode,

          int? FeatureID,

          int? RegionID,

          bool? ShowCustomerNumber,

          bool? ShowEmployees, 

          bool? ShowComments

          );

    }

    public static void Main()

    {

        var queryString = "ReportID=7&DateStart=2021-10-04&DateEnd=2021-12-21&FeatureID=1&ShowCustomerNumber=true&ShowEmployees=true&ShowComments=true&ts=1640086980970";

        var dict = HttpUtility.ParseQueryString(queryString);

        Console.WriteLine(dict);

        var parameters = typeof(IReports).GetMethod("TaskList").GetParameters();

        foreach(var p in parameters)

        {

            // Nullable and null value?

            if((p.ParameterType.IsClass || Nullable.GetUnderlyingType(p.ParameterType) != null) && dict[p.Name] == null)

            {

                Console.WriteLine("Parameter {0} with value null", p.Name);

            }

            else if(dict[p.Name] == null)

            {

                // Not nullable but is not present or null?

                Console.WriteLine("Missing parameter {0}", p.Name);

            }

            else

            {

                // Convert to proper type

                TypeConverter obj = TypeDescriptor.GetConverter(p.ParameterType);

                object val = obj.ConvertFromString(null, CultureInfo.InvariantCulture, dict[p.Name]);

                Console.WriteLine("Parameter {0} with value {1}", p.Name, val);

            }

        }

    }

}