I recently wrote a column on how to open a dialog box in an ASP.NET MVC application. In that column, I had the HTML for the dialog box dynamically generated at runtime from a Partial View and ...

When a request comes in to your ASP.NET site, it's routed through a series of message handlers (in ASP.NET Web API) or modules (in ASP.NET MVC), each of which performs some operation on the request.