tree view and list view for making a shopping cart

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C#

I have made a tree view and list view type SHOPPING CART in c#.Tree view shows different categories of books and when user clicks any of them all the books in that category are displayed in list view.But this is happening only for first node not after that.How do i do that? Plz Help

this is my code but the else if loop is never executed i dont know why?

private void treeView1_NodeMouseDoubleClick(object sender, TreeNodeMouseClickEventArgs e)
{
    TreeNode newselect = e.Node;
    listView1.Items.Clear();
   // string[] arr = new string[2];

    if (e.Node.Text.ToString() == "Art, Design & Fashion")
    {

        listView1.Items.Clear();
        listView1.BeginUpdate();
        display();

        listView1.EndUpdate();
    }

}
void display()
{
    if (treeView1.SelectedNode.Text.ToString() == "Art, Design & Fashion")
    {
        ListViewItem item;
        string[] arr = new string[2];
        arr[0] = "Rugs & Carpets";
        arr[1] = "625";
        item = new ListViewItem(arr);
        listView1.Items.Add(item);
        arr[0] = "The Suit";
        arr[1] = "855";
        item = new ListViewItem(arr);
        listView1.Items.Add(item);
        arr[0] = "Style Mentors";
        arr[1] = "2696";
        item = new ListViewItem(arr);
        listView1.Items.Add(item);
        arr[0] = "Digital Photography";
        arr[1] = "2295";
        item = new ListViewItem(arr);
        listView1.Items.Add(item);
    }
    else if (treeView1.SelectedNode.Text.ToString() == "Entertainment")
    {
        listView1.Items.Clear();
        ListViewItem item;
        string[] arr = new string[2];
        arr[0] = "Rugs & Carpets";
        arr[1] = "625";
        item = new ListViewItem(arr);
        listView1.Items.Add(item);
        arr[0] = "The Suit";
        arr[1] = "855";
        item = new ListViewItem(arr);
        listView1.Items.Add(item);
        arr[0] = "Style Mentors";
        arr[1] = "2696";
        item = new ListViewItem(arr);
        listView1.Items.Add(item);
        arr[0] = "Digital Photography";
        arr[1] = "2295";
        item = new ListViewItem(arr);
        listView1.Items.Add(item);
    }
}