The ClickOnce technology skips all the usual installation steps. Once it starts it checks for prerequisites. If anything is missing it downloads it from a default location. Then it asks the user to click on the Install button to verify that he/she trusts the publisher and wants to install the application. It finally copies the necessary files to a default location on the local hard disk, it creates a desktop and a start menu application shortcut and it launches the application.
The core principles of ClickOnce are to bring the ease of web applications to the Windows user. 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 is not able to 'break' another.
ClickOnce employs CAS (Code Access Security) to ensure that system functions cannot be called by a ClickOnce application from the web, ensuring the security of data and the client system in general.
Read more about this topic: APazari Desktop