Textbox in webform problem ?

  I am using c# , I am using an invoice system . in my page i am having lot of textbox . when my pointer is in any of the textbox . Suppose if the user uses enter key from the keyboard by mistake . My page automatically redirects to some other page . What i want is even if the user press enter key by mistake . Nothing should happen in the page . how to do it

any one
Raghu