<%# %> vs <%= %> [duplicate]

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ASP.NET “special” tags

What is the difference between <%#开发者_StackOverflow ... %>, <%= ... %> and <%$ ... %>?

I couldn't find anything information about this. It's impossible to find "<%=" using a search engine.

Do these tags have a name?

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<%= ... %> is generally equivalent to Response.Write(...) it cannot be used in a control attribute that is runat="server"

<%: ... %> (as of .NET v4.0) is an html encoded version of <%= %> (as @Eric mentions)

<%# ... %> is used in data-binding context for Bind, Eval or Output (as @Ray mentions)

<%$ ... %> is used in the context of a control attribute with runat="server" (google "expression builder" also have a look at making a general purpose 'Code' expression builder. it is evaluated when the attribute/Parameter is required by the control.

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<%# %> will attempt to databind to a data source, using the Bind() function. This makes it a two-way function (read and write).

<%= %> will make the data read-only.

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<%# %> is evaluated during data binding. It does not necessarily require Eval() or Bind() and Matthew suggested - I use it frequently to display plain text in a repeater control.

<%= %> is evaluated as the page renders. It is equivalent to calling Response.Write().

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<%# %> can ONLY be used in data-binding context.

<%= %> expects a string value which it will then include in the output stream. So either a string variable or a method which returns a string. Anything else will cause an error.

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I found some good information that clarifies the terminology for your future google searches:

http://authors.aspalliance.com/aspxtreme/aspnet/syntax/aspnetpagesyntax.aspx

Code Render Blocks:

<% inline code %>

A shortcut for HttpResponse.Write:

<%=inline expression %>

Data Binding Expressions:

<%# databinding expression %>

In a property:

<tagprefix:tagname property = "<%# databinding expression %>" runat="server" />

Server-side comments, such that they do not appear in the client's page source:

<%-- commented out code or content --%>