ASP.NET "special" tags

Question

What is the official name for the "special" ASP.NET tags like this:

<%# %>
<%= %>
<%@ %>
<%$ %>

I can't seem to figure out the conceptual or well known name for these, so I'm having trouble searching for more info. As a bonus, can anyone give me a quick rundown of all of the possible "special tags" and what each one of them does (or point me to a resource)?

Answer 1

No answer for your name question, but the MSDN "ASP.NET Page Syntax" page is pretty good (or rather, that's the top level page; the pages under it give more information).

EDIT: I had previously thought that <%# ... %> wasn't included in the list, but of course it is, under Data-Binding Expressions. Doh.

Answer 2

The official name is "server-side scripting delimiters". Visual Studio 2008 syntax highlighting settings dialog calls these "HTML Server-Side Script".

• <%@ %> is used for page level directives. (<%@Language="C#"%>)
• <% %> is for inclusion of server-side code (<% x = x + 1; %>)
• <%= %> is equivalent of Response.Write();
• <%# %> is used for databinding in ASP.NET Controls.
• <%$ %> is used for expression binding, usually with localized string resources. See http://msdn.microsoft.com/en-us/library/d5bd1tad.aspx
• <%-- --%> is used for server side comments.

There is also

<script runat="server">
</script>

which is the same as <% %>

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Edit to add There's a new one coming in ASP.NET 4.0:

• <%: %> is used to output an HTML encoded string (used in the same way as <%= %>). It automatically HTML encodes its input, unless the input is an IHtmlString (i.e. something that says it knows how to create valid HTML). The intention is that this would all but replace <%= %> (see http://haacked.com/archive/2009/09/25/html-encoding-code-nuggets.aspx)

Answer 3

I have always found this QuickStart page to be very useful, whenever I have a doubt about Server-side syntax. It details 8 different markup styles and provides illustrative examples of each one, in addition to explaining the pros and cons.

It doesn't mention the Page level directive, though, which IIRC is detailed elsewhere in the Quickstart.

Of course, this is relevant to ASP.NET 2.0.