ClickOnce deployment is a Microsoft .NET installation technology that automatically installs and configures a client-side application when a user clicks on a link, such as a link in a Web site, on a CD, or on a universal naming convention (UNC) path. Usually, the application will copy itself to the Temporary Internet Files folder and run within a restricted environment. ClickOnce was introduced with the .NET Framework 2.0 and Visual Studio 2005.
Advantages of ClickOnce Deployment:
1. Best of a rich Windows-based application user experience and the deployment and maintenance benefits of Web applications.
2. Apps automatically download the latest version of themselves.
3. ClickOnce takes the advantage of the Background Intelligent Transfer Service (BITS).
4. Trustworthy deployment model for users to be able to download and execute applications from centrally managed servers without requiring administrator privileges on the client machine.
5. Updates are transacted in a single transcation. (See this to understand “Single Transaction”)
6. The application not only can work offline but it has a degree of control over it; APIs exist, so that the application can find out if it’s online or offline; it can also control its own update process;
7. ClickOnce is integrated with Visual Studio .NET, including the ability to generate the appropriate extra files and tools that help to figure out which security privileges your application need in order to run.
8. Application files can be downloaded on demand or in batches.
9. ClickOnce comes with a Win32 “bootstraper” executable that can download necessary components, even the .NET Framework itself.