ClickOnce

ClickOnce is a deployment technology that enables you to create self-updating Windows-based applications that can be installed and run with minimal user interaction. ClickOnce deployment overcomes three major issues in deployment:

•  Difficulties in updating applications

-          With Microsoft Windows Installer deployment, whenever an application is updated, the user must reinstall the whole application.

-          With ClickOnce deployment, you can provide updates automatically. Only those parts of the application that have changed are downloaded, and then the full, updated application is reinstalled from a new side-by-side folder.

•  Impact to the user's computer

-          With Windows Installer deployment, applications often rely on shared components, with the potential for versioning conflicts.

-          With ClickOnce deployment, each application is self-contained and cannot interfere with other applications.

•  Security permissions

-          Windows Installer deployment requires administrative permissions and allows only limited user installation.

-          ClickOnce deployment enables non-administrative users to install and grants only those Code Access Security permissions necessary for the application.

Developers chose Web applications instead of Windows-based applications, sacrificing the rich user interface and responsiveness of Windows Forms for ease of installation. But now, by using applications deployed using ClickOnce, you can have the best of both technologies.

Simple definition of a ClickOnce application is: any Windows Presentation Foundation, Windows Forms, or console application published using ClickOnce technology. Salient features include:

•  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.
•  ClickOnce applications can be self-updating; they can check for newer versions as they become available and automatically replace any updated files.
•  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. By default, ClickOnce applications run in the Internet or Intranet security zones. If necessary, the application can request elevated security permissions.