Every Web Form page has the property IsPostBack,
which will be true if the page is being loaded in response to a client postback and false if it is being
loaded for the first time.
You can check the value of IsPostBack. If it is false, you know that this is the first time the page is
being displayed, and it's therefore time to get the values out of the database:
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{//... }
}