drop down menu - ASP.NET DropDownList not retaining selected item on postback -

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i have asp dropdownlist gets populated on page_load event, after select item , hit button selected item gets cleared , first item in dropdownlist gets selected. (the dropdownlist populated when page not postback)

help please

   if (!ispostback)     {             list<country> lcountries = new list<country>();             list<companyschedule> lcompanyschedules = new list<companyschedule>();             this.load_countries(lcountries);             this.load_schedules(lcompanyschedules);             if (personnelrec == null)             { personnelrec = new personnel(); }         if (request.querystring["ua"] != null && convert.toint32(request.querystring["ua"].tostring()) > 0)         {             useraccount.id = convert.toint32(request.querystring["ua"].tostring());             app_database.snapshift_select_helper.snapshift_select_personnel_app_account(ref useraccount);         }             this.imgemployeepicture.imageurl = "./images/employees/nophoto.gif";             if (request.querystring["ei"] != null && convert.toint32(request.querystring["ei"].tostring()) > 0)             {                 this.load_personnelrec(convert.toint32(request.querystring["ei"].tostring()));             }             else             {                 this.lblchangedirectionhead.enabled = false;                 this.lblchangedirections.enabled = false;                 this.lbschedules.disabled = true;             }     }

the page lifecycle following (plus other steps irrelevant question):

  1. oninit
  2. populate controls viewstate (during postback)
  3. set selected values (during postback)
  4. page_load

you need have viewstate enabled can populate list before "selects" item. in case, make sure don't repopulate in page_load , lose selected value. if (!ispostback) { // populate }

otherwise, have populate list manually in oninit event on every page request. page_load late in lifecycle, selected item lost.

edit:

the dropdownlist must have valid values set (separate text displayed in browser). done through datavaluefield property. each value must unique, otherwise first duplicate item ever selected. if @ html source in browser, should have:

<select>     <option value="unique_value1">displayed text1</option>     <option value="unique_value2">displayed text2</option> </select>

the unique values used selecting right item on server side.


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