What Is a ClickOnce Application?

A ClickOnce application is any Windows Presentation Foundation (.xbap), Windows Forms (.exe), console application (.exe), or Office solution (.dll) published using ClickOnce technology. You can publish a ClickOnce application in three different ways: from a Web page, from a network file share, or from media such as a CD-ROM. A ClickOnce application can be installed on an end user’s computer and run locally even when the computer is offline, or it can be run in an online-only mode without permanently installing anything on the end user’s computer. For more information, see Choosing a ClickOnce Deployment Strategy.
ClickOnce applications can be self-updating; they can check for newer versions as they become available and automatically replace any updated files. The developer can specify the update behavior; a network administrator can also control update strategies, for example, marking an update as mandatory. Updates can also be rolled back to an earlier version by the end user or by an administrator. For more information, see Choosing a ClickOnce Update Strategy.
Because ClickOnce applications are isolated, installing or running a ClickOnce application cannot break existing applications. ClickOnce applications are self-contained; each ClickOnce application is installed to and run from a secure per-user, per-application cache. ClickOnce applications run in the Internet or Intranet security zones. If necessary, the application can request elevated security permissions. For more information, see Securing ClickOnce Applications.