Output cache in content and master page

Two questions:

1. If I have a content page and a master page and I put t开发者_Go百科his inside my content page:

<%@ OutputCache ...%>

Does it cache the whole page or only the content page portion?

2. How can I apply OutputChace in the master page?

I have a master page that has a lot of content pages that uses it. I want to apply the same outputcache profile on all of them, but I dont want to go one by one and change them.

Thanks.

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The whole page is cached. Edit
You can use user controls to cache portions.

As by the comments, if you want to cache all pages that are using a specific master page, you need the following code in the master page

 protected void Page_Load(object sender, EventArgs e)
        {
            Response.Cache.SetExpires(DateTime.Now.AddMonths(1));
            Response.Cache.SetCacheability(HttpCacheability.ServerAndPrivate);
            Response.Cache.SetValidUntilExpires(true);
        }

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Content page only will be cached; unless that content page is using the master page, in which case master page also will be cached.

Unlike a content page you can't use OutputCache directive for master page. See the below links

Cache Master Page in ASP.NET

http://www.dotnetperls.com/output-cache

http://forums.asp.net/t/1236981.aspx