RadioButtonList.SelectedValue() returning null object

Question

I have a form on a .aspx page with a RadioButtonList. I populate the list using an ArrayList and BindData(). When I try to get the selected value of the list I get a null object.

    protected void Page_Load(object sender, EventArgs e)
{
    q_LBL.Text = "What is the right answer?";
    ArrayList options = new ArrayList();
    options.Add("a");
    options.Add("b");
    options.Add("c");
    options.Add("d");
    options.TrimToSize();
    options_RBL.DataSource = options;
    options_RBL.DataBind();
}

protected void submit_BTN_Click(object sender, EventArgs e)
{
    fb_LBL.Text = options_RBL.SelectedValue;
}

Answer 1

try this

  protected void Page_Load(object sender, EventArgs e)
{
    if(!Page.IsPostBack)
{
    q_LBL.Text = "What is the right answer?";
    ArrayList options = new ArrayList();
    options.Add("a");
    options.Add("b");
    options.Add("c");
    options.Add("d");
    options.TrimToSize();
    options_RBL.DataSource = options;
    options_RBL.DataBind();

}
}

protected void submit_BTN_Click(object sender, EventArgs e)
{
    fb_LBL.Text = options_RBL.SelectedValue;
}