using System;
using static System.Console;
 
public class Program {
    public static void Main() {
        var objeto = new AlgumaClasse();
        objeto.HoraEntrada = DateTime.Now;
        objeto.HoraSaida = DateTime.Now.AddHours(1).AddMinutes(43).AddSeconds(22);
        WriteLine($"Permaneceu {(objeto.TempoPermanencia().ToString(@"hh\:mm"))}");
    }
}
 
class AlgumaClasse {
    public DateTime HoraEntrada { get; set; }
 
    public DateTime HoraSaida { get; set; }
 
	public TimeSpan TempoPermanencia() => HoraSaida - HoraEntrada;
}
 
//https://pt.stackoverflow.com/q/182587/101

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