Question

I am getting the object reference error in this line:
emp[count].emp_id = int.Parse(parts[0]);

in this code

this program to read from file and store in array of object

public partial class Form1 : Form
{
    public Form1()
    {
        InitializeComponent();
    }

    public class employees
    {
        public int emp_id;
        public string firstName;
        public string lastName;
        public double balance;
    }

    private void btnOpen_Click(object sender, EventArgs e)
    {
        OpenFileDialog file = new OpenFileDialog();
        DialogResult result = file.ShowDialog();
        if (result == DialogResult.Cancel) return;

        string fileName = file.FileName;
        StreamReader reader = new StreamReader(fileName);

        string[] lines = File.ReadAllLines(fileName);
        int emp_count = lines.Count<string>();
        employees[] emp = new employees[emp_count];
        int count = 0;
        foreach (string line in lines)
        {
            string[] parts = new string[4];
            parts = line.Split(',');
            **emp[count].emp_id = int.Parse(parts[0]);**
            emp[count].firstName = parts[1];
            emp[count].lastName = parts[2];
            emp[count].balance = double.Parse(parts[3]);
            count++;
            txtGet.Text += emp[count].emp_id + " " + emp[count].firstName + " " + emp[count].lastName + " " + emp[count].balance + " \n ";

        }

Answer 1

You need to initialise emp[count] to something.

You can do this by adding the following:

foreach (string line in lines) 
{ 
    emp[count] = new employees();
    string[] parts = new string[4]; 
    //....
}

When you call employees[] emp = new employees[emp_count]; you initilise emp to an array of employees with the length of emp_count.

emp[0] = null;
emp[1] = null;
//etc.

Each element inside emp also needs to be instantiated before you can use it.