I'm not sure that what you are asking for is exactly what you want - but you are right, it is bad practice to expose fields directly - you should encapsulate them in properties and make those public instead.
But I suspect that won't help you too much with ASPX pages - since the previous page doesn't really exist any more when the new page is displayed, it's going to be difficult to pick up it's properties! What I would suggest is storing the page values in the Session and accessing them from the new page that way:
Session MSDN[
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