c# - dropdown value selecting only first value -

in below c# code though choosing own year still value passed 1920 only. can see values being displayed in dropdown box when choose value , submit 1920 being passed database.

protected void page_load(object sender, eventargs e)     {         dropdownlist3.items.clear();             (int = 1920; <= 2000; i++)             {                 dropdownlist3.items.add(i.tostring());             }     }     protected void button1_click(object sender, eventargs e)     {                 sbtc.dex(dropdownlist3.selecteditem);             } 

can tell me did mistake?

because when click on button again executing code in page_load event. solution set dropdown values once. can use page.ispostback property check whether initial load or postback.

protected void page_load(object sender, eventargs e) {   if(!ispostback)   {         dropdownlist3.items.clear();         (int = 1920; <= 2000; i++)         {             dropdownlist3.items.add(i.tostring());         }   } }