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

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开发者_JS百科 just syntax which we have to remember blindly? What does <% %> mean in general?

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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.

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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 %>