BaseWebDefinitionCustomMasterPageUrl Field

Specifies the default master file. At runtime, the value in this property replaces the ~masterurl/default.master token in content pages. Provide a master page file name for master pages located in '_catalogs/masterpages', a web relative master page URL ('SomeLibrary/file.master') or a server relative page url if the master file is located in a parent web.

public PatternString CustomMasterPageUrl