asp.net网站的ViewSate如何用。

将页面传到过来的ID存到ViewState好不好？
C# code:

ViewState["ID"] = Request.QueryString["ID"];


为什么自己做的网站存在好多隐藏的ViewState，自己做网站与专业网站的比较，为什么存在这么大的差异？

自己的：
HTML code:
<div>
<input type="hidden" name="__EVENTTARGET" id="__EVENTTARGET" value="" />
<input type="hidden" name="__EVENTARGUMENT" id="__EVENTARGUMENT" value="" />
<input type="hidden" name="__LASTFOCUS" id="__LASTFOCUS" value="" />
<input type="hidden" name="__VIEWSTATE" id="__VIEWSTATE" value="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