Uri.IsBaseOf(Uri) is used to compare the current Uri instance to a specified Uri to determine whether this URI is a base for the specified Uri. When comparing two Uri objects to determine a base relationship, the user information (Uri.UserInfo) is not evaluated. When comparing two URIs (uri1 and uri2), uri1 is the base of uri2 if, when you ignore everything in uri2 after the last slash (/), the two URIs are identical. Using http://host/path/path/file?query as the base URI, the following table shows whether it is a base for other URIs.

http://host/path/path/file/	yes
http://host/path/path/#fragment	yes
http://host/path/path/MoreDir/"	yes
http://host/path/path/OtherFile?Query	yes
http://host/path/path/	yes
http://host/path/path/file	yes
http://host/path/path	no
http://host/path/path?query	no
http://host/path/path#Fragment	no
http://host/path/path2/	no
http://host/path/path2/MoreDir	no
http://host/path/File	no

Namespace: System
Assembly: System (in System.dll)
Assembly Versions: 2.0.0.0, 4.0.0.0