ClickOnce

From Wikipedia, the free encyclopedia

ClickOnce is a Microsoft technology for deploying Windows Forms or Windows Presentation Foundation -based software, also called Smart clients. ClickOnce is only available in .NET 2.0 and later. A less advanced technique can be obtained with the Microsoft Updater Application Block. It is similar to Java Web Start for the Java Platform.

1 Description
2 Applications
3 Manifests
4 Updates
5 See also
6 External links
7 Community Sites

[edit] Description

With ClickOnce, installing and running an application is as simple as clicking a link in a web page. The core principles of ClickOnce are to bring the ease and reliability of web applications to thick client Windows applications. Besides that, ClickOnce aims to solve three other problems with conventional deployment models: the difficulty in updating a deployed application, the impact of an application to the user's computer, and the need for administrator permissions to install applications.

ClickOnce-deployed applications are considered 'low impact', in that they are installed per-user, not per-machine. No administrator privileges are required to install one of these applications. Each ClickOnce application is isolated from the other. This means one ClickOnce application cannot 'break' another.

[edit] Applications

The ClickOnce model supports two flavors of applications: installed applications (akin to conventional Windows applications with start menu integration) and online applications (browser hosted applications that are not installed, only run and cached). ClickOnce applications can be deployed to a computer from a Web location, a network share, or even from a file location such as a CD.

The ClickOnce deployment technology is integrated into the Visual Studio 2005 project system and is also natively supported by MSBuild technology.

Currently ClickOnce only works with IE, although the FFClickOnce extension allows Firefox to support it.

[edit] Manifests

A ClickOnce deployment is controlled through the use of two XML manifest files: a deployment manifest and an application manifest. The deployment manifest file describes the deployment model: the current version, update behavior, publisher identity along with digital signature. This manifest is intended to be authored by administrators who handle deployment. The application manifest - a .exe.manifest file - describes the application assemblies, dependent libraries and lists permissions required by the application. This file is intended to be authored by the application developer. In order to launch a ClickOnce application, a user clicks on its deployment manifest file.

[edit] Updates

ClickOnce applications can be self-updating; they can check for newer versions as they become available and automatically replace any updated files. For its installed application flavor, ClickOnce presents several update options. Applications can be configured to check for updates on startup or after startup. ClickOnce also exposes programmatic APIs to customize update behavior. There is also support for required or mandatory updates for managing ongoing updates and ensuring that the entire user-base can be moved up to a new version in a timely manner.