Meaning of the various symbols in .aspx page of asp.net

Question

I have come across different symbols in .aspx page of asp.net

<%#eval(expr) %> 
<%#bind(expr) %>
<% %>  - for specifying the c# code in aspx page
<%$ %> - for specifying the SQL connection string in <asp:SqlDataSource>

Is there any underlying logic behind these symbols or is it just syntax which we have to remember blindly? What does <% %> mean in general?

Supply

Answer 1

It is just syntax.

<% %> is simply short for <script runat="server"> </script> aka code render blocks.

<%# %> are binding expressions (plus the above).

<%= %> is the above + a Response.Write().

<%: %> is the above + a Response.Write() wrapped in Html.Encode (new in .NET 4.0).

<%$ %> is an ASP.NET expression, used to bind configuration or resource file data during runtime.

Beaver

Thanks for your response, could you cite any references on this information? I have tried to find this in documentation many times, with no results. Also, what about <%$ %> ? – Santoyo

@Santoyo - Follow the links. I don't know about <%$ %>. – Beaver

I did some digging based of your initial links and I found out that <%$ %> is called an ASP.NET Expression and allows you to pull values from configuration or resource files. – Santoyo

<% ... %> is not simply short for <script runat=server>! Such blocks (<% ... %>) contain code that becomes a part of the Render() method, while <script runat=server> blocks contain methods and other class members themselves. – Bojorquez

Another construct is <%-- .. --%> for comment blocks (that won't turn up in the resulting HTML). – Domesticate

I realise this is nearly 5 years later, but might be worth adding to your list the <%#: %> notation... which is the HTML encoded version of the binding expression that was added as part of ASP.NET 4.5 – Gothic

Answer 2

Remember it. It's more poorly documented ASP.net syntax to help maintain inconsistencies and fallout from ASP 'classic' groans. Also don't forget

<%=variablename %>  

Unsheathe