I want to determine a part of the time specified in TimeSpan and get it.

using System;
using System.Collections.General;

namespace ConsoleApp1
{
  class program
  {
    static void Main (string[]args)
    {
      DateTimeworkStart = DateTime.Parse("2019-06-21 19:00");
      DateTimeworkEnd=DateTime.Parse("2019-06-2203:00");

      TimeSpanworkMidNight=CalcMidNightWork(workStart,workEnd);

      Console.WriteLine("Workday and Time="+workStart.ToString());
      Console.WriteLine("Date and Time to Leave ="+workEnd.ToString());
      Console.WriteLine("Late Night="+workMidNight.ToString());

      return;
    }

    // PAIR INFORMATION CLASS OF START/END TIME OF CALCULATION TARGET TIME
    public class TimeSpanPair
    {
      public TimeSpan TSSstart {get;set;}
      public TimeSpan TSEnd {get;set;}
    }

    // Calculated Time Zone List—Starting at 00:00 on the calculated date
    staticList<TimeSpanPair>tsMidNight=newList<TimeSpanPair>(){
      newTimeSpanPair() {TSStart=newTimeSpan(0,0,0), TSEnd=newTimeSpan(5,0,0)}, // 00:00 - 05:00
      newTimeSpanPair() {TSStart=newTimeSpan(22,0,0), TSEnd=newTimeSpan(24,0,0)} // 22:00 - 24:00
    };

    /// <summary>
    /// Acquisition of late-night work hours (multiple consecutive days can be calculated)
    /// </summary>
    /// <param name="startTime">Work Date & Time</param>
    /// <param name="endTime">Date </param>
    /// <returns>Late Night Hours</returns>
    staticTimeSpan CalcMidNightWork (DateTime startTime, DateTime endTime)
    {
      TimeSpan result = new TimeSpan(0,0,0,0); // Late Night Working Hours Report Initial Value 00:00
      DateTime workStart = startTime; // Work start time per applicable day
      DateTimeworkDate=workStart.Date;// 00:00 on that day
      DateTime tspStart = workDate; // For calculated (midnight) time zone start time tasks
      DateTime tspEnd=workDate; // For calculated (midnight) time zone end-of-day operations
      do
      {
        workDate=workStart.Date; // Set 00:00 for that day as the calculation base value
        // Loops by the number of elements in the calculated (midnight) time zone list
        foreach (TimeSpanPair tsp intsMidNight)
        {
          tspStart = workDate.Add(tssp.TSStart); // Set the start time of the calculated time zone
          tspEnd=workDate.Add(tssp.TSEnd); // Set the end time of the calculated time zone
          // Determine if the working hours are within the calculated time zone
          if(!(workStart>=tsspEnd)||(endTime<=tsspStart)))
          {
            tspStart=(tspStart<workStart)?workStart:tspStart;//Adjust to actual start time
            tspEnd=(tsspEnd>endTime)?endTime: tspEnd;//Adjust to actual end time
            result+=(tsspEnd-tsspStart);// Calculate the hours worked during the calculated time zone and add it to the reported value
          }
        }
        workStart=workDate.AddDays(1.0); // Start the next day at 00:00
      } while(workStart<endTime);// Loops while working hours remain
      return result;
    }
  }
}

var start=TimeSpan.Parse("19:00"); // This is fluctuating
var end = TimeSpan.Parse("3:00"); // The next day, at 3 o'clock, fluctuates here too
var day = new TimeSpan(1,0,0,0); // 1 day for the next day

TimeSpanans=end+day-start;

var start=TimeSpan.Parse("19:00"); // This is fluctuating
var end = TimeSpan.Parse("3:00"); // The next day, at 3 o'clock, fluctuates here too

if(end<start){
       end = end.Add (TimeSpan.FromDays(1));
       // end+=TimeSpan.FromDays(1); may be
}
TimeSpandiff = end-start;
Console.WriteLine(diff.ToString(@".hh\:mm"));

        TimeSpan CalcCross (TimeSpan begin, TimeSpan end)
        {
            if(end<begin){
                end+=TimeSpan.FromDays(1);
            }
            TimeSpan m1 = TimeSpan.Parse ("22:00");
            TimeSpan m2 = TimeSpan.Parse("1.05:00");

            TimeSpan x1 = Max(begin,m1);
            TimeSpan x2 = Min(end,m2);

            TimeSpan cross=x2-x1;
            if(cross<TimeSpan.Zero)returnTimeSpan.Zero;
            else return cross;
        }

        TimeSpan Min (TimeSpant1, TimeSpant2)
        {
            if(t1>t2)return t2;
            else return t1;
        }

        TimeSpan Max (TimeSpant1, TimeSpant2)
        {
            if(t1>t2)return t1;
            else return t2;
        }

 [Test]
        public void Test1()
        {
            // You can try five patterns.
            Console.WriteLine (CalcCross(TimeSpan.Parse("9:00"), TimeSpan.Parse("19:00")); // Not overlapping 0:00:00
            Console.WriteLine (CalcCross(TimeSpan.Parse("19:00"), TimeSpan.Parse("6:00")); // 7:00:00 including start and end
            Console.WriteLine (CalcCross(TimeSpan.Parse("23:00"), TimeSpan.Parse("1:00")); // 2:00:00 including range
            Console.WriteLine(CalcCross(TimeSpan.Parse("20:00"), TimeSpan.Parse("2:00")); // 4:00:00 with overlapping first half
            Console.WriteLine(CalcCross(TimeSpan.Parse("23:00"), TimeSpan.Parse("6:00")); // Late overlapping 6:00:00
        }