how to call the event onselectionindexchanged in dropdownlist

hi all

  I  am developing a web page.. I am loading some names to the dropdownlist box from the database. When i select the other names in the dropdownlist box, the event handler is not calling. I have used onselectedindexchanged="DropDownList1_SelectedIndexChanged" . If i use Autopostback = true, then the error is coming. The error is :" the DropDownList has a selected index which is not present in the items or no parameter value. But the dropdownlist is displaying all the names present in the database.

How can i solve this?

 thanks in advance...

 

 
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