regarding asp.net in visual studio 2010

hi

i have a problem with settings i.e i created a button in asp.net using visula studio 2010 but i am unable to redirect to the button click event. whenever i double clicked on that button in the design it is redirecting to .aspx but it should redirect to .aspx.cs. Manually i am able to open that .aspx.cs but if i write code for click event it is not accepting.

how to over come this.

thank u in advance.