Clase responsable del manejo del formulario

Form1.cs

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

    private void btnBrowse_Click(object sender, EventArgs e)
    {
        openFileDialog1.Filter = "XML Document (*.xml)|*.xml|All Files (*.*)|*.*";
        var result = openFileDialog1.ShowDialog();
        if (result == DialogResult.OK) {
            txtFileName.Text = openFileDialog1.FileName;
            btnLoad.Enabled = true;
        }
    }

    private void btnLoad_Click(object sender, EventArgs e)
    {
        listView1.Items.Clear();
        var fileName = txtFileName.Text;
        var reader = new MyFileReader();
        reader.ReadFile(fileName, AddItemToListView);
    }

    private void AddItemToListView(string id, string name, string unitPrice, string discontinued)
    {
        var item = new ListViewItem(new string[] { id, name, unitPrice, discontinued });
        listView1.Items.Add(item);
    }
}