Null 参考 c#

Question

Im writing a code where you can search a name and the subjects teaches will pop-up etc..

however I'm not really sure why but i'm getting Object reference not set to an instance of an object error im missing something i know, can someone help me? i tried different methods didn't really work... heres my code:

public partial class MainWindow : Window
    {
        Course my = new Course();
        public class Course
        {

            public string[] Name { get; set; }
            public string[] Subject { get; set; }
            public string[] Hour { get; set; }

            public Course(string[] name, string[] subject, string[] hour)
            {
                this.Name = name;
                this.Subject = subject;
                this.Hour = hour;

            }
        }

        public MainWindow()
        {
            InitializeComponent();


            my.Name[0] = "Ali";
            my.Name[1] = "Sefer";

            my.Subject[0] = "INFORMATIKA";
            my.Subject[1] = "ENGLISH";

            my.Hour[0] = "12";
            my.Hour[1] = "22";

        }

        private void searchButton_Click(object sender, RoutedEventArgs e)
        {
            Find();
        }


        private void Find()
        {

            int index = 0;
            string wanted = wantedName.Text;

            while (my.Name[index] != wanted && (my.Name[index] != "END"))
            {
                index++;
            }
            if (my.Name[index] == wanted)
            {
                outputLabel.Content = " " + my.Name[index] + " "  + my.Subject[index];
            }
            else
            {
                outputLabel.Content = "Name not found";
            }
        }


    }
}

Answer 1

You are using arrays without initializing them. While you have defined a constructor for your Course class that takes values for the arrays, you are using the default constructor. Try calling your own constructor with arguments like

Course my = new Course(new string[2], new string[2], new string[2]);

Before you can assign a value to an element like my.Name[0] , you have to ensure that my.Name is referencing an allocated array, which means there is memory available for your elements.