Tips for Nested Master Pages and VS 2005 Design-Time

There is a cool tip/trick, though, that will allow you to load a design-surface for a page that uses nested master-pages. This will allow you to use all of the control-designers and smart-tasks in design-view for the page (for example: to perform data-binding, auto-format things, and use any of the control wizards), and not have to change any-code to test it at runtime.

The tip/trick works by adding a base-page class to your project or solution that defines a new property called “RuntimeMasterPageFile” of type string. The base-class then overrides the page’s “OnPreInit” method and uses this property to set the Page object’s MasterPageFile at runtime: