Click once application rollback

Question

Is ClickOnce rollback possible?

How can I do that?

Does this application download all files on update?

How can I see which files are downloaded in the update?

Answer 1

You cannot directly roll back a ClickOnce application. You can give the the old version a higher version number and redeploy/publish the application again. See also How can I rollback clickOnce if I have a minimum required version?

Alternatively you can change the server side manifest file to point to the old version of the application as described here: How can I roll-back a ClickOnce application?

All files described in the application manifest file are downloaded when updating a ClickOnce application. The application manifest file has information about all the files in the ClickOnce application. I suggest reading the msdn site on ClickOnce deployment.

Answer 2

Rollback
If you don't specify a minimum required version, users have the ability to rollback one version via the Add/Remove Programs dialog. If you want to rollback the deployment on your server, you need to use all the old files with a new version number (just like @steenhulthin said).

What is downloaded
Only files that have changed are downloaded. ClickOnce hashes all your files and keeps that information in the application manifest (the one without the .application extension, go figure). If the overall ClickOnce version is newer on the server than on the client, it then compares individual file hashes to see what needs downloaded.

What files are downloaded
To see what files are downloaded, use Fiddler. It captures and displays http traffic and is pure awesome. Learn it. Use it. Love it.

Just an extra word of advice. If you're using Visual Studio to publish, stop. Using a tool like Mage takes more effort, but it helps you understand what the heck ClickOnce actually does. When it's boiled down, there's really not a lot to it. Using the Visual Studio publish wizard makes it seem like black magic.