how to handle asp:button with redirecton of page

hi all,

        i use a asp:button on my page, now if i load the page first time and refresh it widhout clicking the button it run properly, but if i press the button once and refresh the page it genrate a warning message and show two option ("Retry OR Cancle"),

now if i use the responce.redirect on button click event the warning message disappere but the output of button click event is not shown on my page.

 i want when i click the button it workes its functionlty, and if i refresh the page without clicking the button it refreshed without warning msg. so how it can be posible with asp:button.

thanking you
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