Transferring item from one listbox to another

protected void btn1_Click(object sender, EventArgs e)
{
    if (lst_employee.SelectedIndex > -1)
    {
        string value = lst_employee.SelectedItem.Value;
        string text = lst_employee.SelectedItem.Text;
        ListItem li = new ListItem();
        li.Text = text;
        li.Value = value;
        lstselected.Items.Add(li);
        lst_employee.Items.Remove(li);
    }
}
protected void btn2_Click(object sender, EventArgs e)
{
    if (lstselected.SelectedIndex > -1)
    {
        string value = lstselected.SelectedItem.Value;
        string text = lstselected.SelectedItem.Text;
        ListItem li1 = new ListItem();
        li1.Value = value;
        li1.Text = text;
        lstselected.Items.Remove(li1);
        lst_employee.Items.Add(li1);
    }
}
protected void btnall_Click(object sender, EventArgs e)
{
    int count = lst_employee.Items.Count;
    if (count != 0)
    {
        for (int i = 0; i < count; i++)
        {
            ListItem item = new ListItem();
            item.Text = lst_employee.Items[i].Text;
            item.Value = lst_employee.Items[i].Value;
            lstselected.Items.Add(item);
        }
    }
    lst_employee.Items.Clear();
}
protected void btnremove_Click(object sender, EventArgs e)
{
    int count = lstselected.Items.Count;
    if (count != 0)
    {
        for (int i = 0; i < count; i++)
        {
            ListItem item = new ListItem();
            item.Text = lstselected.Items[i].Text;
            item.Value = lstselected.Items[i].Value;
            lst_employee.Items.Add(item);
        }
    }
    lstselected.Items.Clear();
}