Databinding

 MSDN - Data-binding expressions are contained within <%# and %> delimiters and use the Eval and Bind functions. The Eval function is used to define one-way (read-only) binding. The Bind function is used for two-way (updatable) binding. In addition to calling Eval and Bind methods to perform data binding in a data-binding expression, you can call any publicly scoped code within the <%# and %> delimiters to execute that code and return a value during page processing.