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  • UDDI
    See definition for Universal Description, Discovery, and Integration.

  • unboxing
    The conversion of an object instance to a value type. See also: boxing, value type.

  • Uniform Resource Identifier (URI)
    A number or name that uniquely identifies an element or attribute. URIs include both Uniform Resource Names (URNs) and Uniform Resource Locators (URLs).

    URIs are a general scheme for locating resources on the Internet that focuses more on the resource and less on the location. In theory, a URI could find the closest copy of a mirrored document or locate a document moved from one site to another.

    Although it is expected that URNs will become more common in the future, when discussing XML today, URIs are URLs in nearly all cases.

  • Universal Description, Discovery, and Integration (UDDI)
    A platform-independent framework functioning like a directory (similar to a telephone book) that provides a way to locate and register Web services on the Internet. The UDDI specification calls for three elements: white pages, which provide business contact information; yellow pages, which organize Web services into categories (for example, credit card authorization services); and green pages, which provide detailed technical information about individual services. The UDDI also contains an operational registry, which is available today.

  • unmanaged code
    Code that is executed directly by the operating system, outside the common language runtime environment. Unmanaged code must provide its own garbage collection, type checking, security support, and so on, unlike managed code, which receives these services from the common language runtime. See also: managed code.

  • user control
    In ASP.NET: A server control that is authored declaratively using the same syntax as an ASP.NET page and is saved as a text file with an .ascx extension. User controls allow page functionality to be partitioned and reused. Upon first request, the page framework parses a user control into a class that derives from System.Web.UI.UserControl and compiles that class into an assembly, which it reuses on subsequent requests. User controls are easy to develop due to their page-style authoring and deployment without prior compilation.

    In Windows Forms: A composite control that provides consistent behavior and user interface within or across applications. The user control can be local to one application or added to a library and compiled into a DLL for use by multiple applications.