dropdownlist change event fires everytime

dear friends

i m using one dropdownlist,one textbox(for searching text)and one datagrid.

i write the selected index change event of dropdown.

now what happens the selected index change event of dropdown fires everytime when i enter text in textbox and click on button then also the selected index change event fires how do i stop this?

i want to fire this event only when i change the index of dropdown.

one note my dropdown is in updatepanel and the autopostback proparty is true.

thanks

shweta

 
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