click button

Have you placed breakpoint in the Event and checked whether event is triggered twice or once?

i never use breakpoint in VS

at first i set breakpoint ,click in the margin indicator bar to the left of search button event and click F5 and run website it runs website like last time (whitout breack point) and in break point window didnt show any thing 

when i write my word in TB and press Enter after that click to search button it shows result at first time

but if i dont press enter i should click search button tewice.

What do you mean "You never use breakpoints"? Without that how will you debug?

I want to know how whether your event is raised or not both the times hence without adding breakpoint you will never know that

every time i use F5 to run program and i dont know how i can use breackpoint exactly

 at first i set breack point in my searchbutton click event it doesnt show any thing

second time i set breakpoint in page_load event

I dont write any thing in my page_load

 protected void Page_Load(object sender, EventArgs e)

    {

    }

this is result when i set break point on page_load

at first it GET search.aspx and load page when i click search button it Page Post Back search.aspx and load search.aspx again when i click search button for second time it Execute procedure and loadsearch.aspx  page and show result.

Then first learn how to debug code in VS

http://www.codeproject.com/Articles/79508/Mastering-Debugging-in-Visual-Studio-2010-A-Beginn

As that is very neccessary