Radio button selected index not working - asp.net

Question

So I have a sipme ASP.NET Web Page that prints the info of one's gender stacked dynamically in a radio button list:
protected void Page_Load(object sender, EventArgs e)
{
String[] genders = new String[2];
genders[0] = "Male";
genders[1] = "Female";
RadioButtonList1.DataSource = genders;
RadioButtonList1.DataBind();
RadioButtonList1.Items.Add(new ListItem("Neutral", "Zero"));
}
protected void Button1_Click(object sender, EventArgs e)
{
lblName.Text = txtName.Text;
lblSurname.Text = txtSurname.Text;
lblEmail.Text = txtMail.Text;
Panel1.Visible = true;
if (RadioButtonList1.SelectedIndex==0) lblGender.Text = "Male";
else lblGender.Text = "Female";
}
However when I launch the site no matter what I select it always writes female it's like the RadioButtonList1.SelectedIndex==0 isn't working.
Any ideas?

Answer 1

Bind radiobuttonlist in page_Load with !IsPostBack condition or your radiobuttonlist will bind every time you post your page. So your radiobuttonlist is reset to index -1 when you click the button_click.
protected void Page_Load(object sender, EventArgs e)
{
if(!IsPostBack)
{
String[] genders = new String[2];
genders[0] = "Male";
genders[1] = "Female";
RadioButtonList1.DataSource = genders;
RadioButtonList1.DataBind();
RadioButtonList1.Items.Add(new ListItem("Neutral", "Zero"));
}
}