public void Add(MusteriDAL musteri)
 {
     try
     {
         ParseMusteriFile();
         MusteriList.Add(musteri);
         using (StreamWriter sw = File.CreateText(@"C:\Users\Yasin\Documents\GitHub\proje2-yetisyagauss\proje2-yetisyagauss\DeuCSC.Proje2.DAL\Data\Musteriler.txt"))
         {
             JsonSerializer serializer = new JsonSerializer();
             serializer.Serialize(sw, MusteriList);
         }
     }
     catch (Exception e)
     {
         Console.WriteLine(e);
     }
 }
 public void Update(MusteriDAL musteri)
 {
     try
     {
         ParseMusteriFile();
         var result = MusteriList.Where(x => x.Id == musteri.Id).FirstOrDefault();
         MusteriList.Remove(result);
         MusteriList.Add(musteri);
         using (StreamWriter sw = File.CreateText(@"C:\Users\Yasin\Documents\GitHub\proje2-yetisyagauss\proje2-yetisyagauss\DeuCSC.Proje2.DAL\Data\Musteriler.txt"))
         {
             sw.Flush();
             JsonSerializer serializer = new JsonSerializer();
             serializer.Serialize(sw, MusteriList);
         }
     }
     catch (Exception e)
     {
         Console.WriteLine(e);
     }
 }